InOutput.cpp

/// IO routines
#ifdef HAVE_VALUES_H
#include <values.h>
#else
#include <float.h>
#endif

#include "ParallelGravity.h"
#include "DataManager.h"
#include "TipsyFile.h"
#include "OrientedBox.h"
#include "Reductions.h"
#include "Writer.h"
#include "InOutput.h"
#include "ckio.h"
#include <errno.h>
#include <float.h>

using namespace TypeHandling;
using namespace SFC;
using namespace std;

template <typename TPos, typename TVel>
void load_tipsy_gas(Tipsy::TipsyReader &r, GravityParticle &p, double dTuFac) 
{
    Tipsy::gas_particle_t<TPos, TVel> gp;
    
    CkMustAssert(r.getNextGasParticle_t(gp), "failed to read gas particle!");
    p.mass = gp.mass;
    p.position = gp.pos;
    p.velocity = gp.vel;
    p.soft = gp.hsmooth;
#ifdef CHANGESOFT
    p.fSoft0 = gp.hsmooth;
#endif
    p.iType = TYPE_GAS;
    p.fDensity = gp.rho;
    p.fMetals() = gp.metals;
    // O and Fe ratio based on Asplund et al 2009
    p.fMFracOxygen() = 0.43*gp.metals;
    p.fMFracIron() = 0.098*gp.metals;
#ifdef DIFFUSION
    p.fMetalsPred() = gp.metals;
    p.fMFracOxygenPred() = 0.43*gp.metals;
    p.fMFracIronPred() = 0.098*gp.metals;
#endif
    p.u() = dTuFac*gp.temp;
    p.uPred() = dTuFac*gp.temp;
    // Initial estimate of sound speed.
    double gamma = GAMMA_NONCOOL;
    double gammam1 = gamma - 1.0;
    p.c() = sqrt(gamma*gammam1*p.uPred());
    p.vPred() = gp.vel;
    p.fBallMax() = FLT_MAX;     // N.B. don't use DOUBLE_MAX here:
                                // fBallMax*fBallMax should not overflow.
    p.fESNrate() = 0.0;
    p.fTimeCoolIsOffUntil() = 0.0;
    p.dTimeFB() = 0.0;
#ifdef NEED_DT
    p.dt = FLT_MAX;
#endif
#ifdef DTADJUST
    p.dtNew() = FLT_MAX;
#ifndef COOLING_NONE
    p.uDot() = 0.0;  // Used in initial timestep
#endif
    p.PdV() = 0.0;  // Used in initial timestep
#endif
#ifdef SUPERBUBBLE
    p.cpHotInit() = 0;
    p.uHot() = 0.0;
    p.uHotPred() = 0.0;
    p.uHotDot() = 0.0;
    p.massHot() = 0.0;
    p.fThermalCond() = 0.0;
    p.fPromoteSum() = 0.0;
    p.fPromoteSumuPred() = 0.0;
    p.fPromoteuPredInit() = 0.0;
#endif
}

template <typename TPos, typename TVel>
void load_tipsy_dark(Tipsy::TipsyReader &r, GravityParticle &p) 
{
    Tipsy::dark_particle_t<TPos, TVel> dp;
    CkMustAssert(r.getNextDarkParticle_t(dp), "failed to read dark particle!");
	p.mass = dp.mass;
	p.position = dp.pos;
	p.velocity = dp.vel;
	p.soft = dp.eps;
#ifdef CHANGESOFT
	p.fSoft0 = dp.eps;
#endif
	p.fDensity = 0.0;
	p.iType = TYPE_DARK;
#ifdef COLLISION
    p.dtKep = 0;
    p.vPred() = dp.vel;
    p.dtCol = DBL_MAX;
    p.iOrderCol = -1;
    p.w = Vector3D<double>(0.);
#endif
}

template <typename TPos, typename TVel>
void load_tipsy_star(Tipsy::TipsyReader &r, GravityParticle &p) 
{
    Tipsy::star_particle_t<TPos, TVel> sp;

    CkMustAssert(r.getNextStarParticle_t(sp), "failed to read star particle!");
    p.mass = sp.mass;
    p.position = sp.pos;
    p.velocity = sp.vel;
    p.soft = sp.eps;
#ifdef CHANGESOFT
    p.fSoft0 = sp.eps;
#endif
#ifdef COLLISION
    p.dtCol = DBL_MAX;
    p.iOrderCol = -1;
    p.w = Vector3D<double>(0.);
#endif
    p.fDensity = 0.0;
    p.iType = TYPE_STAR;
    p.fStarMetals() = sp.metals;
    // Metals to O and Fe based on Asplund et al 2009
    p.fStarMFracOxygen() = 0.43*sp.metals;
    p.fStarMFracIron() = 0.098*sp.metals;
    p.fMassForm() = sp.mass;
    p.fTimeForm() = sp.tform;
    p.iGasOrder() = -1;
#ifdef COOLING_MOLECULARH 
#ifdef SHIELDSF
    p.fShieldForm() = 0;
#endif
    p.dStarLymanWerner() = 0.0;
#endif
}

/// @brief determine if we are on a TreePiece that will read
/// particles.
/// @param iIndex thisIndex of my TreePiece
/// @param nPieces Total number of TreePieces.
/// @return True if we are on a loading PE, false otherwise
///
/// We only want one TreePiece per PE to open and read the tipsy
/// file.  This saves file opens/closes and reduces the number of
/// messages needed for the initial domain decomposition.

static bool isLoadingPiece(int iIndex, int nPieces)
{
    bool bLoading = true;       ///< return value
    
    int nLoadingPEs = CkNumPes();
#ifdef ROUND_ROBIN_WITH_OCT_DECOMP 
    /// In this case, the pieces have been assigned to PEs in round-robin.
    if(iIndex >= nLoadingPEs) bLoading = false;
#else
    /// The following is based on the DefaultMap procNum().  See
    /// cklocation.C:compute_binsize() in the charm++ source code.
    /// The first (nPiece % nPE) PEs have one more Piece than the rest.

    int nPiecesPerPE = nPieces/nLoadingPEs;
    int nRem = nPieces - nPiecesPerPE*nLoadingPEs;

    int nSmallBlockSize = nPiecesPerPE; 
    int nLargeBlockSize = nPiecesPerPE + 1; 
    int nLargeBlocks = nRem; 
    int iLargeBlockBound = nLargeBlocks * nLargeBlockSize; 
    if (iIndex < iLargeBlockBound) {
        if (iIndex % nLargeBlockSize > 0) {
            bLoading = false;      // not the first piece in a large block
        }
    }
    else {
        if ((iIndex - iLargeBlockBound) % nSmallBlockSize > 0) {
            bLoading = false; // not the first piece in a small block
        }
    }
#endif
    return bLoading;
}

void TreePiece::loadTipsy(const std::string& filename,
			  const double dTuFac, // Convert Temperature
                          const bool bDoublePos,
                          const bool bDoubleVel,
			  const CkCallback& cb) {
        LBTurnInstrumentOff();
        basefilename = filename;

	Tipsy::TipsyReader r(filename, bDoublePos, bDoubleVel);
	if(!r.status()) {
		cerr << thisIndex << ": TreePiece: Fatal: Couldn't open tipsy file!" << endl;
		cb.send(0);	// Fire off callback
		return;
	}
	
	Tipsy::header tipsyHeader = r.getHeader();
	nTotalParticles = tipsyHeader.nbodies;
	nTotalSPH = tipsyHeader.nsph;
	nTotalDark = tipsyHeader.ndark;
	nTotalStar = tipsyHeader.nstar;
	dStartTime = tipsyHeader.time;

        bool skipLoad = !isLoadingPiece(thisIndex, numTreePieces);

        if(skipLoad){
          myNumParticles = 0;
          nStartRead = -1;
          contribute(cb);
          return;
        }

        // find your load offset into input file
        int myIndex = CkMyPe();
        int numLoadingPEs = CkNumPes();
	myNumParticles = nTotalParticles / numLoadingPEs;
	int excess = nTotalParticles % numLoadingPEs;
	int64_t startParticle = ((int64_t) myNumParticles) * myIndex;
	if(myIndex < excess) {
	    myNumParticles++;
	    startParticle += myIndex;
	    }
	else {
	    startParticle += excess;
	    }
	if(startParticle >= nTotalParticles) {
	    CkError("Bad startParticle: %ld, nPart: %ld, myIndex: %d, nLoading: %d\n",
		    startParticle, nTotalParticles, myIndex, numLoadingPEs);
	    }
	CkAssert(startParticle < nTotalParticles);
        nStartRead = startParticle;
	
	if(verbosity > 2)
		cerr << "TreePiece " << thisIndex << " PE " << CkMyPe() << " Taking " << myNumParticles
		     << " of " << nTotalParticles
		     << " particles: [" << startParticle << "," << startParticle+myNumParticles << ")" << endl;

	// allocate an array for myParticles
	nStore = (int)((myNumParticles + 2)*(1.0 + dExtraStore));
	myParticles = new GravityParticle[nStore];
	// Are we loading SPH?
	if(startParticle < nTotalSPH) {
	    if(startParticle + myNumParticles <= nTotalSPH)
		myNumSPH = myNumParticles;
	    else
		myNumSPH = nTotalSPH - startParticle;
	    }
	else {
	    myNumSPH = 0;
	    }
	nStoreSPH = (int)(myNumSPH*(1.0 + dExtraStore));
	if(nStoreSPH > 0)
	    mySPHParticles = new extraSPHData[nStoreSPH];
	// Are we loading stars?
	if(startParticle + myNumParticles > nTotalSPH + nTotalDark) {
	    if(startParticle <= nTotalSPH + nTotalDark)
		myNumStar = startParticle + myNumParticles
		    - (nTotalSPH + nTotalDark);
	    else
		myNumStar = myNumParticles;
	    }
	else {
	    myNumStar = 0;
	    }
	allocateStars();
	
    CkMustAssert(r.seekParticleNum(startParticle), "Couldn't seek to my particles!");
	
	Tipsy::gas_particle gp;
	Tipsy::dark_particle dp;
	Tipsy::star_particle sp;

	int iSPH = 0;
	int iStar = 0;
	for(unsigned int i = 0; i < myNumParticles; ++i) {
		if(i + startParticle < (unsigned int) tipsyHeader.nsph) {
                    myParticles[i+1].extraData = &mySPHParticles[iSPH];
                    if(!bDoublePos)
                        load_tipsy_gas<float,float>(r, myParticles[i+1],
                                                    dTuFac) ;
                    else if(!bDoubleVel)
                        load_tipsy_gas<double,float>(r, myParticles[i+1],
                                                     dTuFac) ;
                    else
                        load_tipsy_gas<double,double>(r, myParticles[i+1],
                                                      dTuFac) ;
                    iSPH++;
		} else if(i + startParticle < (unsigned int) tipsyHeader.nsph
			  + tipsyHeader.ndark) {
                    if(!bDoublePos)
                        load_tipsy_dark<float,float>(r, myParticles[i+1]);
                    else if(!bDoubleVel)
                        load_tipsy_dark<double,float>(r, myParticles[i+1]);
                    else
                        load_tipsy_dark<double,double>(r, myParticles[i+1]);
		} else {
                    myParticles[i+1].extraData = &myStarParticles[iStar];
                    if(!bDoublePos)
                        load_tipsy_star<float,float>(r, myParticles[i+1]);
                    else if(!bDoubleVel)
                        load_tipsy_star<double,float>(r, myParticles[i+1]);
                    else
                        load_tipsy_star<double,double>(r, myParticles[i+1]);
                    iStar++;
		}
                // File corruption checks
                CkAssert(myParticles[i+1].mass >= 0.0);
                CkAssert(myParticles[i+1].soft >= 0.0);
#ifdef SIDMINTERACT
		myParticles[i+1].iNSIDMInteractions = 0;
#endif
		myParticles[i+1].rung = 0;
		myParticles[i+1].fBall = 0.0;
		myParticles[i+1].iOrder = i + startParticle;
#ifdef SPLITGAS
		if(myParticles[i+1].iOrder < tipsyHeader.nsph) myParticles[i+1].iSplitOrder() = i + startParticle;
		if(myParticles[i+1].iOrder >= tipsyHeader.nsph) myParticles[i+1].iOrder +=  tipsyHeader.nsph;
#endif
#if COSMO_STATS > 1
		myParticles[i+1].intcellmass = 0;
		myParticles[i+1].intpartmass = 0;
		myParticles[i+1].extcellmass = 0;
		myParticles[i+1].extpartmass = 0;
#endif
#if COSMO_STATS > 0
		piecemass += myParticles[i+1].mass;
#endif
		boundingBox.grow(myParticles[i+1].position);
	}
  myParticles[0].key = firstPossibleKey;
  myParticles[myNumParticles+1].key = lastPossibleKey;
  contribute(cb);
}

/// @brief return maximum iOrders.
/// Like the above, but the file has already been read
void TreePiece::getMaxIOrds(const CkCallback& cb)
{
    CmiInt8 nMaxOrd[3] = {0, 0, 0}; // 0 -> gas, 1 -> dark, 2 -> all

    for(int i = 0; i < myNumParticles; i++) {
        int64_t dummy;
        dummy = myParticles[i+1].iOrder;
        if(dummy > nMaxOrd[0] && myParticles[i+1].isGas())
            nMaxOrd[0] = dummy;
        if(dummy > nMaxOrd[1] && myParticles[i+1].isDark())
            nMaxOrd[1] = dummy;
        if(dummy > nMaxOrd[2])
            nMaxOrd[2] = dummy;
        }
    contribute(3*sizeof(CmiInt8), nMaxOrd, CkReduction::max_long, cb);
    }

void TreePiece::readTipsyArray(OutputParams& params, const CkCallback& cb)
{
    params.dm = dm; // pass cooling information
    FILE *infile = CmiFopen((params.fileName+"." + params.sTipsyExt).c_str(),
                            "r+");
    if(infile == NULL)
        CkError("Bad open of %s.%s: %s\n", params.fileName.c_str(),
                params.sTipsyExt.c_str(), strerror(errno));
    CkMustAssert(infile != NULL, "Cannot open tipsy array file\n");
    // Check if its a binary file
    unsigned int iDum;
    XDR xdrs;
    xdrstdio_create(&xdrs, infile, XDR_DECODE);
    xdr_u_int(&xdrs,&iDum);
    xdr_destroy(&xdrs);
    if(iDum == nTotalParticles) { // We've got a binary file; read it
        int64_t seek_pos;
        if(params.bVector)
            seek_pos = sizeof(iDum) + nStartRead*(int64_t)sizeof(float)*3;
        else
            seek_pos = sizeof(iDum) + nStartRead*(int64_t)sizeof(float);
        fseek(infile, seek_pos, SEEK_SET);
        xdrstdio_create(&xdrs, infile, XDR_DECODE);
        for(unsigned int i = 0; i < myNumParticles; ++i) {
            if(params.bFloat) {
                if(params.bVector) {
                    Vector3D<float> vValue;
                    xdr_template(&xdrs, &vValue);
                    params.setVValue(&myParticles[i+1], vValue);
                }
                else {
                    float dValue;
                    xdr_float(&xdrs, &dValue);
                    params.setDValue(&myParticles[i+1], dValue);
                }
            }
            else {
                int iValue;
                xdr_template(&xdrs, &iValue);
                params.setIValue(&myParticles[i+1], iValue);
                }
            }
        xdr_destroy(&xdrs);
    }
    else {                      // assume we've got an ASCII file
        int64_t nTot;
        fseek(infile, 0, SEEK_SET);
        int nread;
        nread = fscanf(infile, "%ld\n", &nTot);
        CkAssert(nread == 1);
        int nDim = 1;           // Dimensions to read
        if(params.bVector) {
            nDim = 3;
        }
        for(int iDim = 0; iDim < nDim; iDim++) {
            for(int i = 0; i < nStartRead; i++) {
                double dummy;
                nread = fscanf(infile, "%lf\n", &dummy);
                CkAssert(nread == 1);
            }
            for(int i = 0; i < myNumParticles; i++) {
                if(params.bFloat) {
                    double dDummy;
                    nread = fscanf(infile, "%lf\n", &dDummy);
                    CkAssert(nread == 1);
                    if(params.bVector) {
                        Vector3D<double> vDummy
                            = params.vValue(&myParticles[i+1]);
                        vDummy[iDim] = dDummy;
                        params.setVValue(&myParticles[i+1], vDummy);
                    }
                    else
                        params.setDValue(&myParticles[i+1], dDummy);
                }
                else {
                    int64_t iDummy;
                    nread = fscanf(infile, "%ld\n", &iDummy);
                    CkAssert(nread == 1);
                    params.setIValue(&myParticles[i+1], iDummy);
                }
            }
        }
    }
        
    CmiFclose(infile);
    contribute(cb);
    }

static double fh_time; // gross, but quick way to get time

/// Returns total number of particles in a given file
/// @param filename data file of interest
int64_t ncGetCount(std::string filename)
{
    FILE* infile = CmiFopen(filename.c_str(), "rb");
    if(!infile) {
	return 0;  // Assume there is none of this particle type
	}

    XDR xdrs;
    FieldHeader fh;
    xdrstdio_create(&xdrs, infile, XDR_DECODE);

    if(!xdr_template(&xdrs, &fh)) {
	throw XDRException("Couldn't read header from file!");
	}
    if(fh.magic != FieldHeader::MagicNumber) {
	throw XDRException("This file does not appear to be a field file (magic number doesn't match).");
	}
    if(fh.dimensions != 3 && fh.dimensions != 1) {
	throw XDRException("Wrong dimension.");
	}
    fh_time = fh.time;
    xdr_destroy(&xdrs);
    fclose(infile);
    return fh.numParticles;
    }

static void *readFieldData(const std::string filename, FieldHeader &fh, unsigned int dim,
    int64_t numParticles, int64_t startParticle)
{
    FILE* infile = CmiFopen(filename.c_str(), "rb");
    if(!infile) {
	string smess("Couldn't open field file: ");
	smess += filename;
	throw XDRException(smess);
	}

    XDR xdrs;
    xdrstdio_create(&xdrs, infile, XDR_DECODE);

    if(!xdr_template(&xdrs, &fh)) {
	throw XDRException("Couldn't read header from file!");
	}
    if(fh.magic != FieldHeader::MagicNumber) {
	throw XDRException("This file does not appear to be a field file (magic number doesn't match).");
	}
    if(fh.dimensions != dim) {
	throw XDRException("Wrong dimension of positions.");
	}

    void* data = readField(fh, &xdrs, numParticles, startParticle);
	
    if(data == 0) {
	throw XDRException("Had problems reading in the field");
	}
    xdr_destroy(&xdrs);
    fclose(infile);
    return data;
    }

/// @brief load attributes common to all particles
static void load_NC_base(std::string filename, int64_t startParticle,
                        int myNum, GravityParticle *myParts)
{
    FieldHeader fh;
    // Positions
    if(verbosity && startParticle == 0)
        CkPrintf("loading positions\n");

    void *data = readFieldData(filename + "/pos", fh, 3, myNum,
        startParticle);
    for(int i = 0; i < myNum; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].position = static_cast<Vector3D<float> *>(data)[i];
	    break;
	case float64:
            myParts[i].position = static_cast<Vector3D<double> *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
    // velocities
    if(verbosity && startParticle == 0)
        CkPrintf("loading velocities\n");
    data = readFieldData(filename + "/vel", fh, 3, myNum,
        startParticle);
    for(int i = 0; i < myNum; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].velocity = static_cast<Vector3D<float> *>(data)[i];
	    break;
	case float64:
            myParts[i].velocity = static_cast<Vector3D<double> *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
    // masses
    if(verbosity && startParticle == 0)
        CkPrintf("loading masses\n");

    data = readFieldData(filename + "/mass", fh, 1, myNum,
        startParticle);
    for(int i = 0; i < myNum; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].mass = static_cast<float *>(data)[i];
	    break;
	case float64:
            myParts[i].mass = static_cast<double *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
    // softenings
    if(verbosity && startParticle == 0)
        CkPrintf("loading softenings\n");

    data = readFieldData(filename + "/soft", fh, 1, myNum,
        startParticle);
    for(int i = 0; i < myNum; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].soft = static_cast<float *>(data)[i];
#ifdef CHANGESOFT
            myParts[i].fSoft0 = static_cast<float *>(data)[i];
#endif
	    break;
	case float64:
            myParts[i].soft = static_cast<double *>(data)[i];
#ifdef CHANGESOFT
            myParts[i].fSoft0 = static_cast<double *>(data)[i];
#endif
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
}

static void load_NC_gas(std::string filename, int64_t startParticle,
                        int myNumSPH, GravityParticle *myParts,
                        extraSPHData *mySPHParts, double dTuFac)
{
    if(verbosity && startParticle == 0)
        CkPrintf("loading gas\n");

    load_NC_base(filename, startParticle, myNumSPH, myParts);

    for(int i = 0; i < myNumSPH; ++i) {
        myParts[i].iType = TYPE_GAS;
        myParts[i].extraData = &mySPHParts[i];
        myParts[i].fBallMax() = FLT_MAX;  // N.B. don't use DOUBLE_MAX here:
                                          // fBallMax*fBallMax should not overflow.
        myParts[i].fESNrate() = 0.0;
        myParts[i].fTimeCoolIsOffUntil() = 0.0;
        myParts[i].dTimeFB() = 0.0;
#ifdef NEED_DT
        myParts[i].dt = FLT_MAX;
#endif
#ifdef DTADJUST
        myParts[i].dtNew() = FLT_MAX;
#ifndef COOLING_NONE
        myParts[i].uDot() = 0.0;  // Used in initial timestep
#endif
        myParts[i].PdV() = 0.0;  // Used in initial timestep
#endif
#ifdef SUPERBUBBLE
        myParts[i].cpHotInit() = 0;
        myParts[i].uHot() = 0.0;
        myParts[i].uHotPred() = 0.0;
        myParts[i].uHotDot() = 0.0;
        myParts[i].massHot() = 0.0;
        myParts[i].fThermalCond() = 0.0;
        myParts[i].fPromoteSum() = 0.0;
        myParts[i].fPromoteSumuPred() = 0.0;
        myParts[i].fPromoteuPredInit() = 0.0;
#endif
        }

    FieldHeader fh;
    // Density
    if(verbosity && startParticle == 0)
        CkPrintf("loading densities\n");

    void *data = readFieldData(filename + "/GasDensity", fh, 1, myNumSPH,
                               startParticle);
    for(int i = 0; i < myNumSPH; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].fDensity = static_cast<float *>(data)[i];
	    break;
	case float64:
            myParts[i].fDensity = static_cast<double *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
  if(ncGetCount(filename + "/OxMassFrac") > 0) {
    // Oxygen
    if(verbosity && startParticle == 0)
        CkPrintf("loading Oxygen\n");

    data = readFieldData(filename + "/OxMassFrac", fh, 1, myNumSPH,
                               startParticle);
    for(int i = 0; i < myNumSPH; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].fMFracOxygen() = static_cast<float *>(data)[i];
	    break;
	case float64:
            myParts[i].fMFracOxygen() = static_cast<double *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
  }
  if(ncGetCount(filename + "/FeMassFrac") > 0) {
    // Iron
    if(verbosity && startParticle == 0)
        CkPrintf("loading Iron\n");

    data = readFieldData(filename + "/FeMassFrac", fh, 1, myNumSPH,
                               startParticle);
    for(int i = 0; i < myNumSPH; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].fMFracIron() = static_cast<float *>(data)[i];
	    break;
	case float64:
            myParts[i].fMFracIron() = static_cast<double *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
  }
    // Temperature
    if(verbosity && startParticle == 0)
        CkPrintf("loading temperature\n");

    data = readFieldData(filename + "/temperature", fh, 1, myNumSPH,
                               startParticle);
    for(int i = 0; i < myNumSPH; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].u() = dTuFac*static_cast<float *>(data)[i];
	    break;
	case float64:
            myParts[i].u() = dTuFac*static_cast<double *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        myParts[i].uPred() = myParts[i].u();
        // Initial estimate of sound speed.
        double gamma = GAMMA_NONCOOL;
        double gammam1 = gamma - 1.0;
        myParts[i].c() = sqrt(gamma*gammam1*myParts[i].uPred());
        }
    deleteField(fh, data);
}

static void load_NC_dark(std::string filename, int64_t startParticle,
                        int myNumDark, GravityParticle *myParts)
{
    if(verbosity && startParticle == 0)
        CkPrintf("loading darks\n");
    
    load_NC_base(filename, startParticle, myNumDark, myParts);

#ifdef COLLISION
    if(verbosity && startParticle == 0)
        CkPrintf("loading spins\n");

    FieldHeader fh;
    void *data = readFieldData(filename + "/spin", fh, 3, myNumDark,
                               startParticle);
    for(int i = 0; i < myNumDark; ++i) {
	    switch(fh.code) {
	    case float32:
                myParts[i].w = static_cast<Vector3D<float> *>(data)[i];
	        break;
	    case float64:
                myParts[i].w = static_cast<Vector3D<double> *>(data)[i];
	        break;
	    default:
	        throw XDRException("I don't recognize the type of this field!");
	        }
        }
    deleteField(fh, data);
#endif

    for(int i = 0; i < myNumDark; ++i) {
        myParts[i].fDensity = 0.0;
        myParts[i].iType = TYPE_DARK;
        }
}

static void load_NC_star(std::string filename, int64_t startParticle,
                         int myNumStar, GravityParticle *myParts,
                         extraStarData *myStarParts)
{
    if(verbosity && startParticle == 0)
        CkPrintf("loading stars\n");

    for(int i = 0; i < myNumStar; ++i) {
        myParts[i].iType = TYPE_STAR;
        myParts[i].extraData = &myStarParts[i];
        myParts[i].fDensity = 0.0;
        myParts[i].iGasOrder() = -1;
        }
    load_NC_base(filename, startParticle, myNumStar, myParts);

    FieldHeader fh;
    // Oxygen
    if(verbosity && startParticle == 0)
        CkPrintf("loading Oxygen\n");

    void *data = readFieldData(filename + "/OxMassFrac", fh, 1, myNumStar,
                               startParticle);
    for(int i = 0; i < myNumStar; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].fStarMFracOxygen() = static_cast<float *>(data)[i];
	    break;
	case float64:
            myParts[i].fStarMFracOxygen() = static_cast<double *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
    // Iron
    if(verbosity && startParticle == 0)
        CkPrintf("loading Iron\n");

    data = readFieldData(filename + "/FeMassFrac", fh, 1, myNumStar,
                               startParticle);
    for(int i = 0; i < myNumStar; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].fStarMFracIron() = static_cast<float *>(data)[i];
	    break;
	case float64:
            myParts[i].fStarMFracIron() = static_cast<double *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
    // Formation Time
    if(verbosity && startParticle == 0)
        CkPrintf("loading timeform\n");

    data = readFieldData(filename + "/timeform", fh, 1, myNumStar,
                               startParticle);
    for(int i = 0; i < myNumStar; ++i) {
	switch(fh.code) {
	case float32:
            myParts[i].fTimeForm() = static_cast<float *>(data)[i];
	    break;
	case float64:
            myParts[i].fTimeForm() = static_cast<double *>(data)[i];
	    break;
	default:
	    throw XDRException("I don't recognize the type of this field!");
	    }
        }
    deleteField(fh, data);
    for(int i = 0; i < myNumStar; ++i) {
        myParts[i].fMassForm() = myParts[i].mass;
#ifdef COOLING_MOLECULARH 
        myParts[i].dStarLymanWerner() = 0.0;
#ifdef SHIELDSF
        myParts[i].fShieldForm() = 0;
#endif
#endif
        }
}

void TreePiece::loadNChilada(const std::string& filename,
                             const double dTuFac, // Convert Temperature
			     const CkCallback& cb) {
        LBTurnInstrumentOff();
        basefilename = filename;

	nTotalSPH = ncGetCount(filename + "/gas/pos");
	nTotalDark = ncGetCount(filename + "/dark/pos");
	nTotalStar = ncGetCount(filename + "/star/pos");
	nTotalParticles = nTotalSPH + nTotalDark + nTotalStar;
    CkMustAssert(nTotalParticles > 0, "No particles can be read.  Check file permissions\n");
	dStartTime = fh_time;

        bool skipLoad = !isLoadingPiece(thisIndex, numTreePieces);

        if(skipLoad){
          myNumParticles = 0;
          nStartRead = -1;
          contribute(cb);
          return;
        }

        // find your load offset into input file
        int myIndex = CkMyPe();
        int numLoadingPEs = CkNumPes();
	myNumParticles = nTotalParticles / numLoadingPEs;
	int excess = nTotalParticles % numLoadingPEs;
	int64_t startParticle = ((int64_t)myNumParticles) * myIndex;
	if(myIndex < excess) {
	    myNumParticles++;
	    startParticle += myIndex;
	    }
	else {
	    startParticle += excess;
	    }
	if(startParticle >= nTotalParticles) {
	    CkError("Bad startParticle: %ld, nPart: %ld, myIndex: %d, nLoading: %d\n",
		    startParticle, nTotalParticles, myIndex, numLoadingPEs);
	    }
	CkAssert(startParticle < nTotalParticles);
        nStartRead = startParticle;
	
	if(verbosity > 2)
		cerr << "TreePiece " << thisIndex << " PE " << CkMyPe() << " Taking " << myNumParticles
		     << " of " << nTotalParticles
		     << " particles: [" << startParticle << "," << startParticle+myNumParticles << ")" << endl;

	// allocate an array for myParticles
	nStore = (int)((myNumParticles + 2)*(1.0 + dExtraStore));
	myParticles = new GravityParticle[nStore];
	// Are we loading SPH?
	if(startParticle < nTotalSPH) {
	    if(startParticle + myNumParticles <= nTotalSPH)
		myNumSPH = myNumParticles;
	    else
		myNumSPH = nTotalSPH - startParticle;
	    }
	else {
	    myNumSPH = 0;
	    }
	nStoreSPH = (int)(myNumSPH*(1.0 + dExtraStore));
	if(nStoreSPH > 0)
	    mySPHParticles = new extraSPHData[nStoreSPH];
	// Are we loading stars?
	if(startParticle + myNumParticles > nTotalSPH + nTotalDark) {
	    if(startParticle <= nTotalSPH + nTotalDark)
		myNumStar = startParticle + myNumParticles
		    - (nTotalSPH + nTotalDark);
	    else
		myNumStar = myNumParticles;
	    }
	else {
	    myNumStar = 0;
	    }
	allocateStars();
	
        if(myNumSPH > 0) {
            load_NC_gas(filename + "/gas", startParticle, myNumSPH,
                        &myParticles[1], mySPHParticles, dTuFac);
            }
        int myNumDark = myNumParticles - myNumSPH - myNumStar;
        startParticle -= nTotalSPH;
        if(startParticle < 0)
            startParticle = 0;
        if(myNumDark > 0) {
            load_NC_dark(filename + "/dark", startParticle, myNumDark,
                         &myParticles[myNumSPH + 1]);
            }
        startParticle = nStartRead - nTotalSPH - nTotalDark;
        if(startParticle < 0)
            startParticle = 0;
        if(myNumStar > 0) {
            load_NC_star(filename + "/star", startParticle, myNumStar,
                         &myParticles[myNumSPH + myNumDark + 1],
                         myStarParticles);
            }
        for(int i = 0; i < myNumParticles; ++i) {
            myParticles[i+1].rung = 0;
            myParticles[i+1].fBall = 0.0;
            myParticles[i+1].iOrder = i + nStartRead;
#ifdef SIDMINTERACT
            myParticles[i+1].iNSIDMInteractions = 0;
#endif
#ifdef SPLITGAS
            if(myParticles[i+1].iOrder < nTotalSPH) myParticles[i+1].iSplitOrder() = i + nStartRead;
            if(myParticles[i+1].iOrder >= nTotalSPH) myParticles[i+1].iOrder  += nTotalSPH;
#endif
            boundingBox.grow(myParticles[i+1].position);
        }
        
  myParticles[0].key = firstPossibleKey;
  myParticles[myNumParticles+1].key = lastPossibleKey;
  contribute(cb);
}

/// Generic read of binary (NChilada) array format into floating point
/// or integer particle attribute  (NOTE MISNOMER)
void TreePiece::readFloatBinary(OutputParams& params, int bParaRead,
    const CkCallback& cb)
{
    FieldHeader fh;
    void *data;
    int64_t startParticle = nStartRead;
    params.dm = dm; // pass cooling information
    
    if((params.iType & TYPE_GAS) && (myNumSPH > 0)) {
        data = readFieldData(params.fileName + "/gas/" + params.sNChilExt, fh,
            1, myNumSPH, nStartRead);
        for(int i = 0; i < myNumSPH; ++i) {
            switch(fh.code) {
            case int32:
                params.setIValue(&myParticles[i+1], static_cast<int *>(data)[i]);
                break;
            case int64:
                params.setIValue(&myParticles[i+1], static_cast<int64_t *>(data)[i]);
                break;
            case float32:
                params.setDValue(&myParticles[i+1], static_cast<float *>(data)[i]);
                break;
            case float64:
                params.setDValue(&myParticles[i+1], static_cast<double *>(data)[i]);
                break;
            default:
                throw XDRException("I don't recognize the type of this field!");
                }
            }
        deleteField(fh, data);
        }
    int myNumDark = myNumParticles - myNumSPH - myNumStar;
    startParticle -= nTotalSPH;
    if(startParticle < 0) startParticle = 0;
    if((params.iType & TYPE_DARK) && (myNumDark > 0)) {
        data = readFieldData(params.fileName + "/dark/" + params.sNChilExt, fh,
            1, myNumDark, startParticle);
        for(int i = 0; i < myNumDark; ++i) {
            switch(fh.code) {
            case int32:
                params.setIValue(&myParticles[myNumSPH+i+1], static_cast<int *>(data)[i]);
                break;
            case int64:
                params.setIValue(&myParticles[myNumSPH+i+1], static_cast<int64_t *>(data)[i]);
                break;
            case float32:
                params.setDValue(&myParticles[myNumSPH+i+1], static_cast<float *>(data)[i]);
                break;
            case float64:
                params.setDValue(&myParticles[myNumSPH+i+1], static_cast<double *>(data)[i]);
                break;
            default:
                throw XDRException("I don't recognize the type of this field!");
                }
            }
        deleteField(fh, data);
        }
    startParticle = nStartRead - nTotalSPH - nTotalDark;
    if(startParticle < 0)
        startParticle = 0;
    if((params.iType & TYPE_STAR) && (myNumStar > 0)) {
        data = readFieldData(params.fileName + "/star/" + params.sNChilExt, fh,
            1, myNumStar, startParticle);
        for(int i = 0; i < myNumStar; ++i) {
            switch(fh.code) {
            case int32:
                params.setIValue(&myParticles[myNumSPH+myNumDark+i+1], static_cast<int *>(data)[i]);
                break;
            case int64:
                params.setIValue(&myParticles[myNumSPH+myNumDark+i+1], static_cast<int64_t *>(data)[i]);
                break;
            case float32:
                params.setDValue(&myParticles[myNumSPH+myNumDark+i+1], static_cast<float *>(data)[i]);
                break;
            case float64:
                params.setDValue(&myParticles[myNumSPH+myNumDark+i+1], static_cast<double *>(data)[i]);
                break;
            default:
                throw XDRException("I don't recognize the type of this field!");
                }
            }
        deleteField(fh, data);
        }
    contribute(cb);
}

/// @brief Find starting offsets and begin parallel write.
///
/// Perform Parallel Scan (a log(p) algorithm) to establish start of
/// parallel writes, then do the writing.  Calls writeTipsy() to do
/// the actual writing.
void Writer::setupWrite(int iStage, // stage of scan
			   u_int64_t iPrevOffset,
			   const std::string& filename,
			   const double dTime,
			   const double dvFac,
			   const double duTFac,
                           const bool bDoublePos,
                           const bool bDoubleVel,
			   const int bCool,
			   const CkCallback& cb)
{
    if(iStage > nSetupWriteStage + 1) {
	// requeue message
	thisProxy[thisIndex].setupWrite(iStage, iPrevOffset, filename,
				     dTime, dvFac, duTFac, bDoublePos,
                                     bDoubleVel, bCool, cb);
	return;
	}
    nSetupWriteStage++;
    if(iStage == 0)
	nStartWrite = 0;
    
    int iOffset = 1 << nSetupWriteStage;
    nStartWrite += iPrevOffset;
    if(thisIndex+iOffset < (int) CkNumPes()) { // Scan on
	if(verbosity > 1) {
	    ckerr << thisIndex << ": stage " << iStage << " sending "
		  << nStartWrite+vMyParticles.size() << " to "
                  << thisIndex+iOffset << endl;
	    }
	thisProxy[thisIndex+iOffset].setupWrite(iStage+1,
                                                nStartWrite+vMyParticles.size(),
                                                filename, dTime, dvFac, duTFac,
                                                bDoublePos, bDoubleVel, bCool, cb);
	}
    if(thisIndex < iOffset) { // No more messages are coming my way
	// send out all the messages
	for(iStage = iStage+1; (1 << iStage) + thisIndex < (int)CkNumPes();
	    iStage++) {
	    iOffset = 1 << iStage;
	    if(verbosity > 1) {
		ckerr << thisIndex << ": stage " << iStage << " sending "
		      << nStartWrite+vMyParticles.size() << " to "
		      << thisIndex+iOffset << endl;
		}
            thisProxy[thisIndex+iOffset].setupWrite(iStage+1,
                                                    nStartWrite+vMyParticles.size(),
                                                    filename, dTime, dvFac,
                                                    duTFac, bDoublePos,
                                                    bDoubleVel, bCool, cb);
	    }
        if(thisIndex == (int) CkNumPes()-1)
            assert(nStartWrite+vMyParticles.size() == nTotalParticles);
	nSetupWriteStage = -1;	// reset for next time.
	parallelWrite(0, cb, filename, dTime, dvFac, duTFac, bDoublePos,
                      bDoubleVel, bCool);
	}
    }

/// @brief Control the parallelism in the tipsy output by breaking it
/// up into nIOProcessor pieces.
/// @param iPass What pass we are on in the parallel write.  The
/// initial call should be with "0".

void Writer::parallelWrite(int iPass, const CkCallback& cb,
			      const std::string& filename, const double dTime,
			      const double dvFac, // scale velocities
			      const double duTFac, // convert temperature
                              const bool bDoublePos,
                              const bool bDoubleVel,
			      const int bCool)
{
    Tipsy::header tipsyHeader;

    tipsyHeader.time = dTime;
    tipsyHeader.nbodies = nTotalParticles;
    tipsyHeader.nsph = nTotalSPH;
    tipsyHeader.nstar = nTotalStar;
    tipsyHeader.ndark = nTotalParticles - (nTotalSPH + nTotalStar);

    if(nIOProcessor == 0) {	// use them all
	Tipsy::TipsyWriter wAll(filename, tipsyHeader, false, bDoublePos,
                                bDoubleVel);
	writeTipsy(wAll, vMyParticles, dvFac, duTFac, bDoublePos, bDoubleVel,
                   bCool);
	contribute(cb);
	return;
	}
    int nSkip = CkNumPes()/nIOProcessor;
    if(nSkip == 0)
	nSkip = 1;
    if(thisIndex%nSkip != iPass) { // N.B. this will only be the case
				   // for the first pass.
	return;
	}

    Tipsy::TipsyWriter w(filename, tipsyHeader, false, bDoublePos, bDoubleVel);
    writeTipsy(w, vMyParticles, dvFac, duTFac, bDoublePos, bDoubleVel, bCool);
    if(iPass < (nSkip - 1) && thisIndex < (CkNumPes() - 1))
	thisProxy[thisIndex+1].parallelWrite(iPass + 1, cb, filename, dTime,
					     dvFac, duTFac, bDoublePos,
                                             bDoubleVel, bCool);
    contribute(cb);
    }


/// @brief Serial output of tipsy file.
///
/// Send my particles to piece 0 for output.
///
void Writer::serialWrite(const u_int64_t iPrevOffset, // previously written
							 //particles
			    const std::string& filename,  // output file
			    const double dTime,	 // time or expansion
			    const double dvFac,  // velocity conversion
			    const double duTFac, // temperature conversion
                            const bool bDoublePos,
                            const bool bDoubleVel,
			    const int bCool,
			    const CkCallback& cb)
{
    int *piSph = NULL;
    if(vMySPHParticles.size() > 0)
	piSph = new int[vMySPHParticles.size()];
    int *piStar = NULL;
    if(vMyStarParticles.size() > 0)
	piStar = new int[vMyStarParticles.size()];
    /*
     * Calculate offsets to send across processors
     */
    int iGasOut = 0;
    int iStarOut = 0;
    for(int iPart = 0; iPart < vMyParticles.size() ; iPart++) {
	if(vMyParticles[iPart].isGas()) {
	    piSph[iGasOut] = (extraSPHData *)vMyParticles[iPart].extraData
		- &vMySPHParticles[0];
	    iGasOut++;
	    }
	if(vMyParticles[iPart].isStar()) {
	    piStar[iStarOut] = (extraStarData *)vMyParticles[iPart].extraData
		- &vMyStarParticles[0];
	    iStarOut++;
	    }
	}
    thisProxy[0].oneNodeWrite(thisIndex, vMySPHParticles.size(),
                              vMyStarParticles.size(),
			   vMyParticles, vMySPHParticles, vMyStarParticles,
			   piSph, piStar, iPrevOffset, filename, dTime,
			   dvFac, duTFac, bDoublePos, bDoubleVel, bCool, cb);
    if(vMySPHParticles.size() > 0)
	delete [] piSph;
    if(vMyStarParticles.size() > 0)
	delete [] piStar;
    }

/// @brief a global variable to store the tipsy writing state for
/// serial I/O.
///
/// Since this is for serial I/O there are no issues for multiple
/// cores accessing this.
///
Tipsy::TipsyWriter *globalTipsyWriter;

/// @brief write out the particles I have been sent
void
Writer::oneNodeWrite(int iIndex, // Index of Treepiece
			int iOutSPH, // number of SPH particles
			int iOutStar, // number of Star particles
                     std::vector<GravityParticle> vParticles, // particles to write
                     std::vector<extraSPHData> vGas, // SPH data
                     std::vector<extraStarData> vStar, // Star data
			int *piSPH, // SPH data offsets
			int *piStar, // Star data offsets
			const u_int64_t iPrevOffset, // previously written
						    //particles
			const std::string& filename,  // output file
			const double dTime,	 // time or expansion
			const double dvFac,  // velocity conversion
			const double duTFac, // temperature conversion
                        const bool bDoublePos,
                        const bool bDoubleVel,
			const int bCool,
			const CkCallback& cb)
{
    /*
     * Calculate offsets from across processors
     */
    int iGasOut = 0;
    int iStarOut = 0;
    for(int iPart = 0; iPart < vParticles.size(); iPart++) {
	if(vParticles[iPart].isGas()) {
	    vParticles[iPart].extraData = vGas.data() + piSPH[iGasOut];
	    iGasOut++;
	    }
	if(vParticles[iPart].isStar()) {
	    vParticles[iPart].extraData = vStar.data() + piStar[iStarOut];
	    iStarOut++;
	    }
	}
    nStartWrite = iPrevOffset;
    if(iIndex == 0) {
        // Create and truncate output file.    
        FILE *fp = CmiFopen(filename.c_str(), "w");
        if(fp == NULL) {
            ckerr << "Treepiece " << thisIndex << " failed to open "
                  << filename.c_str() << " : " << errno << ":" << strerror(errno) << endl;
            CkAbort("Bad file open!");
        }
        CmiFclose(fp);
        
	Tipsy::header tipsyHeader;

	tipsyHeader.time = dTime;
	tipsyHeader.nbodies = nTotalParticles;
	tipsyHeader.nsph = nTotalSPH;
	tipsyHeader.nstar = nTotalStar;
	tipsyHeader.ndark = nTotalParticles - (nTotalSPH + nTotalStar);
    
	globalTipsyWriter = new Tipsy::TipsyWriter(filename, tipsyHeader,
                                                   false, bDoublePos,
                                                   bDoubleVel);
	}
	    
    writeTipsy(*globalTipsyWriter, vParticles, dvFac, duTFac, bDoublePos,
               bDoubleVel, bCool);
    
    if(iIndex < (CkNumPes() - 1))
	thisProxy[iIndex+1].serialWrite(iPrevOffset + vParticles.size(), filename,
					dTime, dvFac, duTFac, 
                                        bDoublePos, bDoubleVel, bCool, cb);
    else {
	delete globalTipsyWriter;
	cb.send();  // we are done.
	}
    }
    
template <typename TPos, typename TVel>
void write_tipsy_gas(Tipsy::TipsyWriter &w, GravityParticle &p,
                     const double dvFac,
                     const double duTFac,
                     const int bCool,
                     COOL *Cool) 
{
    Tipsy::gas_particle_t<TPos, TVel> gp;

    gp.mass = p.mass;
    gp.pos = p.position;
    gp.vel = p.velocity*dvFac;
#ifdef CHANGESOFT
    gp.hsmooth = p.fSoft0;
#else
    gp.hsmooth = p.soft;
#endif
    gp.phi = p.potential;
    gp.rho = p.fDensity;
    gp.metals = p.fMetals();
    if(bCool) {
#ifndef COOLING_NONE
#ifdef COOLING_GRACKLE
        gp.temp = CoolCodeEnergyToTemperature(Cool, &p.CoolParticle(), p.u(),
                                              p.fDensity, p.fMetals());
#else
        gp.temp = CoolCodeEnergyToTemperature(Cool, &p.CoolParticle(), p.u(),
                                              p.fMetals());
#endif
#else
        CkAbort("cooling output without cooling code");
#endif
        }
    else 
        gp.temp = duTFac*p.u();

    if(!w.putNextGasParticle_t(gp)) {
        CkError("[%d] Write gas failed, errno %d: %s\n", CkMyPe(), errno, strerror(errno));
        CkAbort("Bad Write");
        }
}

template <typename TPos, typename TVel>
void write_tipsy_dark(Tipsy::TipsyWriter &w, GravityParticle &p,
                     const double dvFac) 
{
    Tipsy::dark_particle_t<TPos, TVel> dp;

    dp.mass = p.mass;
    dp.pos = p.position;
    dp.vel = p.velocity*dvFac;
#ifdef CHANGESOFT
    dp.eps = p.fSoft0;
#else
    dp.eps = p.soft;
#endif
    dp.phi = p.potential;

    if(!w.putNextDarkParticle_t(dp)) {
        CkError("[%d] Write dark failed, errno %d: %s\n", CkMyPe(), errno, strerror(errno));
        CkAbort("Bad Write");
    }
}

template <typename TPos, typename TVel>
void write_tipsy_star(Tipsy::TipsyWriter &w, GravityParticle &p,
                     const double dvFac) 
{
    Tipsy::star_particle_t<TPos, TVel> sp;

    sp.mass = p.mass;
    sp.pos = p.position;
    sp.vel = p.velocity*dvFac;
#ifdef CHANGESOFT
    sp.eps = p.fSoft0;
#else
    sp.eps = p.soft;
#endif
    sp.phi = p.potential;
    sp.metals = p.fStarMetals();
    sp.tform = p.fTimeForm();

    if(!w.putNextStarParticle_t(sp)) {
        CkError("[%d] Write star failed, errno %d: %s\n", CkMyPe(), errno, strerror(errno));
        CkAbort("Bad Write");
    }
}

void Writer::writeTipsy(Tipsy::TipsyWriter& w,
                        std::vector<GravityParticle>& vParticles,
			   const double dvFac, // scale velocities
			   const double duTFac, // convert temperature
                           const bool bDoublePos,
                           const bool bDoubleVel,
			   const int bCool)
{
    
    if(nStartWrite == 0)
	w.writeHeader();
    if(vParticles.size() == 0)     // no particles to write
        return;
    
    CkMustAssert(w.seekParticleNum(nStartWrite), "bad seek");
    for(unsigned int i = 0; i < vParticles.size(); i++) {
	if(vParticles[i].isGas()) {
            if(!bDoublePos)
                write_tipsy_gas<float,float>(w, vParticles[i], dvFac,
                                             duTFac, bCool, dm->Cool);
            else if(!bDoubleVel)
                write_tipsy_gas<double,float>(w, vParticles[i], dvFac,
                                              duTFac, bCool, dm->Cool);
            else
                write_tipsy_gas<double,double>(w, vParticles[i], dvFac,
                                               duTFac, bCool, dm->Cool);
                
	    }
	else if(vParticles[i].isDark()) {
            if(!bDoublePos)
                write_tipsy_dark<float,float>(w, vParticles[i], dvFac);
            else if(!bDoubleVel)
                write_tipsy_dark<double,float>(w, vParticles[i], dvFac);
            else
                write_tipsy_dark<double,double>(w, vParticles[i], dvFac);
	    }
	else if(vParticles[i].isStar()) {
            if(!bDoublePos)
                write_tipsy_star<float,float>(w, vParticles[i], dvFac);
            else if(!bDoubleVel)
                write_tipsy_star<double,float>(w, vParticles[i], dvFac);
            else
                write_tipsy_star<double,double>(w, vParticles[i], dvFac);
	    }
	else {
	    CkAbort("Bad particle type in tipsyWrite");
	    }
	}
    }

static bool compIOrder(const GravityParticle& first,
		       const GravityParticle & second)
{
    if(first.iOrder < second.iOrder)
	return true;
    return false;
    }

///
/// @brief Calculate boundaries based on iOrder
///
inline int64_t iOrderBoundaries(int nPieces, int iPiece, int64_t nMaxOrder) 
{
    if(iPiece == nPieces)
        return nMaxOrder+1;

    // Note that with particle creation/destruction this will not be
    // perfectly balanced.
    //
    int64_t nOutParticles = nMaxOrder/ nPieces;
    return nOutParticles * iPiece;
    }

///
/// @brief Perform operations to prepare for output.
///
void Main::reOrder() {
    ckout << "Reordering ...";
    double startTime = CkWallTimer();
    writeProxy.clear(nTotalParticles, nTotalSPH, nTotalDark, nTotalStar,
                     CkCallbackResumeThread());
    treeProxy.fillWriters(nMaxOrder);
    CkWaitQD(); // Wait until Writers are filled.
    writeProxy.reOrder(CkCallbackResumeThread());
    ckout << " took " << (CkWallTimer() - startTime) << " seconds." << endl;
}

///
/// @brief 
/// @param _nMaxOrder Maximum iOrder used to calculate TreePiece
/// boundaries for output.
///
void TreePiece::fillWriters(int64_t _nMaxOrder)
{
    LBTurnInstrumentOff();      // The load balancer should not
                                // measure output timings.
    nMaxOrder = _nMaxOrder;

    if (myNumParticles > 0) {
	// Sort particles in iOrder
	sort(myParticles+1, myParticles+myNumParticles+1, compIOrder);

	// Tag boundary particle to avoid overruns
	myParticles[myNumParticles+1].iOrder = nMaxOrder+1;
    
	// Loop through to get particle counts.
	GravityParticle *binBegin = &myParticles[1];
	GravityParticle *binEnd;
	for(int iPe = 0; iPe < CkNumPes(); iPe++) {
            int64_t nextStartParticle = iOrderBoundaries(CkNumPes(), iPe+1, nMaxOrder);
	    for(binEnd = binBegin; binEnd->iOrder < nextStartParticle;
		binEnd++);
	    int nPartOut = binEnd - binBegin;
            if(nPartOut > 0) {
                std::vector<GravityParticle> vPartOut;
                std::vector<extraSPHData> vSPHOut;
                std::vector<extraStarData> vStarOut;

                for(GravityParticle *pPart = binBegin; pPart < binEnd; pPart++) {
                    vPartOut.push_back(*pPart);
                    if(pPart->isGas()) {
                        vSPHOut.push_back(*(extraSPHData *)pPart->extraData);
		    }
                    if(pPart->isStar()) {
			vStarOut.push_back(*(extraStarData *)pPart->extraData);
		    }
		}
                if (verbosity>=3)
                    CkPrintf("me:%d to:%d how many:%ld\n",thisIndex, iPe,
                             (binEnd-binBegin));
                writeProxy[iPe].receive(vPartOut, vSPHOut, vStarOut);
	    }
            if(&myParticles[myNumParticles+1] <= binEnd)
                break;
	    binBegin = binEnd;
	    }
	}
    }

/// @brief Initialize the data structures in preparation for receiving
/// particles for writing.
/// @param nTotal Total number of particles in the snapshot
/// @param nSPH Total number of SPH particles in the snapshot
/// @param nDark Total number of Dark particles in the snapshot
/// @param nStar Total number of Star particles in the snapshot
/// @param cb Callback when done.
void Writer::clear(int64_t nTotal, int64_t nSPH, int64_t nDark, int64_t nStar,
                   const CkCallback& cb)
{
    nTotalParticles = nTotal;
    nTotalSPH = nSPH;
    nTotalDark = nDark;
    nTotalStar = nStar;
    vMyParticles.clear();
    vMySPHParticles.clear();
    vMyStarParticles.clear();
    dm = (DataManager*)CkLocalNodeBranch(dataManagerID);
    contribute(cb);
}

///
/// @brief Accumulate particle data from the TreePieces.
/// @param vPart Particle data
/// @param vSPH  extraData for SPH particles
/// @param vStar  extraData for Star particles
///
void Writer::receive(std::vector<GravityParticle> vPart, std::vector<extraSPHData> vSPH,
                     std::vector<extraStarData> vStar) 
{
    vMyParticles.insert(vMyParticles.end(), vPart.begin(), vPart.end());
    vMySPHParticles.insert(vMySPHParticles.end(), vSPH.begin(), vSPH.end());
    vMyStarParticles.insert(vMyStarParticles.end(), vStar.begin(), vStar.end());
}


/// @ brief Reorder particles according to iOrder once they have all
/// been received
void Writer::reOrder(const CkCallback &cb) {
    // assign gas data pointers
    int iGas = 0;
    int iStar = 0;
    for(int iPart = 0; iPart < vMyParticles.size(); iPart++) {
	if(vMyParticles[iPart].isGas()) {
	    vMyParticles[iPart].extraData = (void *)&vMySPHParticles[iGas];
	    iGas++;
        }
	if(vMyParticles[iPart].isStar()) {
	    vMyParticles[iPart].extraData = (void *)&vMyStarParticles[iStar];
	    iStar++;
        }
    }

    std::sort(vMyParticles.begin(), vMyParticles.end(), compIOrder);
    contribute(cb);
}

// Output a Tipsy ASCII array file.
void Writer::outputASCII(OutputParams& params, // specifies
						  // filename, format,
						  // and quantity to
						  // be output
			    int bParaWrite,	  // Every processor
						  // can write.  If
						  // false, all output
						  // gets sent to
						  // treepiece "0" for writing.
			    const CkCallback& cb) {
  FILE* outfile;
  int *aiOut;	// array for oneNode I/O
  double *adOut;	// array for oneNode I/O
  Vector3D<double> *avOut;	// array for one node I/O
  params.dm = dm; // pass cooling information
  
  if((thisIndex==0 && packed) || (thisIndex==0 && !packed && cnt==0)) {
    if(verbosity > 2)
      ckout << "Writer " << thisIndex << ": Writing header for output file" << endl;
    outfile = CmiFopen((params.fileName+"."+params.sTipsyExt).c_str(), "w");
    CkAssert(outfile != NULL);
    fprintf(outfile,"%d\n",(int) nTotalParticles);
    CmiFclose(outfile);
  }
	
  if(verbosity > 3)
    ckout << "Writer " << thisIndex << ": Writing output to disk" << endl;
	
  if(bParaWrite) {
      outfile = CmiFopen((params.fileName+"."+params.sTipsyExt).c_str(), "a");
      if(outfile == NULL)
	    ckerr << "Writer " << thisIndex << " failed to open "
		  << params.fileName.c_str() << " : " << errno << endl;
      CkAssert(outfile != NULL);
      }
  else {
      if(params.bFloat) {
          if(params.bVector && packed)
              avOut = new Vector3D<double>[vMyParticles.size()];
          else
              adOut = new double[vMyParticles.size()];
          }
      else
          aiOut = new int[vMyParticles.size()];
      }
  for(unsigned int i = 0; i < vMyParticles.size(); ++i) {
      Vector3D<double> vOut;
      double dOut;
      int iOut;
      if(params.bFloat) {
          if(params.bVector) {
              vOut = params.vValue(&vMyParticles[i]);
              if(!packed){
                  if(cnt==0)
                      dOut = vOut.x;
                  if(cnt==1)
                      dOut = vOut.y;
                  if(cnt==2)
                      dOut = vOut.z;
                  }
              }
          else
              dOut = params.dValue(&vMyParticles[i]);
          }
      else
          iOut = params.iValue(&vMyParticles[i]);
      
      if(bParaWrite) {
        if(params.bFloat) {
	  if(params.bVector && packed){
	      if(fprintf(outfile,"%.14g\n",vOut.x) < 0) {
		  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
		    CkAbort("Badness");
		    }
	      if(fprintf(outfile,"%.14g\n",vOut.y) < 0) {
		  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
		  CkAbort("Badness");
		  }
	      if(fprintf(outfile,"%.14g\n",vOut.z) < 0) {
		  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
		  CkAbort("Badness");
		  }
	      }
	  else {
	      if(fprintf(outfile,"%.14g\n",dOut) < 0) {
		  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
		  CkAbort("Badness");
		  }
	      }
            }
        else {
            if(fprintf(outfile,"%d\n", iOut) < 0) {
                ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
                CkAbort("Badness");
                }
            }
	  }
      else {
        if(params.bFloat) {
	  if(params.bVector && packed)
	      avOut[i] = vOut;
	  else
	      adOut[i] = dOut;
	  }
        else
            aiOut[i] = iOut;
        }
      }
  cnt++;
  if(cnt == 3 || !params.bVector)
      cnt = 0;
  
  if(bParaWrite) {
      int result = CmiFclose(outfile);
      if(result != 0)
	    ckerr << "Bad close: " << strerror(errno) << endl;
      CkAssert(result == 0);

      if(thisIndex!=(int)CkNumPes()-1) {
	  thisProxy[thisIndex + 1].outputASCII(params, bParaWrite, cb);
	  return;
	  }

      if(packed || !params.bVector || (!packed && cnt==0)) {
	  cb.send(); // We are done.
	  return;
	  }
      // go through pieces again for unpacked vector.
      thisProxy[0].outputASCII(params, bParaWrite, cb);
      }
  else {
      int bDone = packed || !params.bVector || (!packed && cnt==0); // flag for last time
      if(params.bFloat) {
          if(params.bVector && packed) {
              thisProxy[0].oneNodeOutVec(params, avOut, vMyParticles.size(),
                                         thisIndex, bDone, cb);
              delete [] avOut;
              }
          else {
              thisProxy[0].oneNodeOutArr(params, adOut, vMyParticles.size(),
                                         thisIndex, bDone, cb);
              delete [] adOut;
              }
          }
      else {
          thisProxy[0].oneNodeOutIntArr(params, aiOut, vMyParticles.size(),
                                        thisIndex, cb);
          delete [] aiOut;
          }
      }
}

// Receives an array of vectors to write out in ASCII format
// Assumed to be called from outputASCII() and will continue with the
// next tree piece unless "bDone".
void Writer::oneNodeOutVec(OutputParams& params,
			      Vector3D<double>* avOut, // array to be output
			      int nPart, // number of elements in avOut
			      int iIndex, // treepiece which called me
			      int bDone, // Last call
			      const CkCallback& cb)
{
    FILE* outfile = CmiFopen((params.fileName+"."+params.sTipsyExt).c_str(), "a");
    if(outfile == NULL)
	ckerr << "Writer " << thisIndex << " failed to open "
	      << params.fileName.c_str() << " : " << errno << endl;
    CkAssert(outfile != NULL);
    for(int i = 0; i < nPart; ++i) {
	if(fprintf(outfile,"%.14g\n",avOut[i].x) < 0) {
	  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
	    CkAbort("Badness");
	    }
	if(fprintf(outfile,"%.14g\n",avOut[i].y) < 0) {
	  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
	  CkAbort("Badness");
	  }
	if(fprintf(outfile,"%.14g\n",avOut[i].z) < 0) {
	  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
	  CkAbort("Badness");
	  }
	}
    int result = CmiFclose(outfile);
    if(result != 0)
	ckerr << "Bad close: " << strerror(errno) << endl;
    CkAssert(result == 0);

    if(iIndex!=(int)CkNumPes()-1) {
	  thisProxy[iIndex + 1].outputASCII(params, 0, cb);
	  return;
	  }

    if(bDone) {
	  cb.send(); // We are done.
	  return;
	  }
    CkAbort("packed array Done logic wrong");
    }

// Receives an array of doubles to write out in ASCII format
// Assumed to be called from outputASCII() and will continue with the
// next tree piece unless "bDone"

void Writer::oneNodeOutArr(OutputParams& params,
			      double *adOut, // array to be output
			      int nPart, // length of adOut
			      int iIndex, // treepiece which called me
			      int bDone, // Last call
			      const CkCallback& cb)
{
    FILE* outfile = CmiFopen((params.fileName+"."+params.sTipsyExt).c_str(), "a");
    if(outfile == NULL)
	ckerr << "Writer " << thisIndex << " failed to open "
	      << params.fileName.c_str() << " : " << errno << endl;
    CkAssert(outfile != NULL);
    for(int i = 0; i < nPart; ++i) {
	if(fprintf(outfile,"%.14g\n",adOut[i]) < 0) {
	  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
	    CkAbort("Badness");
	    }
	}
    int result = CmiFclose(outfile);
    if(result != 0)
	ckerr << "Bad close: " << strerror(errno) << endl;
    CkAssert(result == 0);

    if(iIndex!=(int)CkNumPes()-1) {
	  thisProxy[iIndex + 1].outputASCII(params, 0, cb);
	  return;
	  }

    if(bDone) {
	  cb.send(); // We are done.
	  return;
	  }
    // go through pieces again for unpacked vector.
    thisProxy[0].outputASCII(params, 0, cb);
    }

// Receives an array of ints to write out in ASCII format
// Assumed to be called from outputASCII() and will continue with the
// next tree piece.

void Writer::oneNodeOutIntArr(OutputParams& params,
			      int *aiOut, // array to be output
			      int nPart, // length of adOut
			      int iIndex, // treepiece which called me
			      const CkCallback& cb)
{
    FILE* outfile = CmiFopen((params.fileName+"."+params.sTipsyExt).c_str(), "a");
    if(outfile == NULL)
	ckerr << "Writer " << thisIndex << " failed to open "
	      << params.fileName.c_str() << " : " << errno << endl;
    CkAssert(outfile != NULL);
    for(int i = 0; i < nPart; ++i) {
	if(fprintf(outfile,"%d\n",aiOut[i]) < 0) {
	  ckerr << "Writer " << thisIndex << ": Error writing array to disk, aborting" << endl;
	    CkAbort("Badness");
	    }
	}
    int result = CmiFclose(outfile);
    if(result != 0)
	ckerr << "Bad close: " << strerror(errno) << endl;
    CkAssert(result == 0);
    if(iIndex!=(int)CkNumPes()-1) {
	  thisProxy[iIndex + 1].outputASCII(params, 0, cb);
	  return;
	  }

    cb.send(); // We are done.
    }

/// Output a Tipsy or NChilada XDR binary float array file.
void Main::outputBinary(OutputParams& params, // specifies
                                              // filename, format,
                                              // and quantity to
                                              // be output
                        int bParaWrite,	      // Every processor can write.
                        const CkCallback& cb) {

    // Save params and callback
    pOutput = &params;
    cbIO = cb;
    Ck::IO::Options opts;
        opts.basePE = 0;
    if(bParaWrite) {
        if(param.nIOProcessor == 0) {
            opts.activePEs = CkNumNodes();
            }
        else {
            opts.activePEs = param.nIOProcessor;
            }
        }
    else {
        opts.activePEs = 1;
        }
    
    params.iTypeWriting = 0;
    if(params.iBinaryOut != 6) {
        Ck::IO::open(params.fileName+"."+params.sTipsyExt,
                     CkCallback(CkIndex_Main::cbOpen(0), thishandle),
                     opts);
        }
    else {
        std::string strFile = getNCNextOutput(params);
        if(strFile.empty()) { // No data to write
            cb.send();
            return;
            }
        Ck::IO::open(strFile,
                     CkCallback(CkIndex_Main::cbOpen(0), thishandle),
                     opts);
        }
}

/// Return the file name of the next nchilada output to write (gas,
/// dark or star).  Returns empty if we are done.  Also advances the
/// iTypeWriting in params.
std::string Main::getNCNextOutput(OutputParams& params) 
{
    if(params.iTypeWriting == 0) {
        params.iTypeWriting = TYPE_GAS;
        if((params.iType & TYPE_GAS) && (nTotalSPH > 0)) {
            NCgasNames.push_back(params.sNChilExt);
            return params.fileName+"/gas/"+params.sNChilExt;
            }
        }
    if(params.iTypeWriting == TYPE_GAS) {
        params.iTypeWriting = TYPE_DARK;
        if((params.iType & TYPE_DARK) && (nTotalDark > 0)) {
            NCdarkNames.push_back(params.sNChilExt);
            return params.fileName+"/dark/"+params.sNChilExt;
            }
        }
    if(params.iTypeWriting == TYPE_DARK) {
        params.iTypeWriting = TYPE_STAR;
        if((params.iType & TYPE_STAR) && (nTotalStar > 0)) {
            NCstarNames.push_back(params.sNChilExt);
            return params.fileName+"/star/"+params.sNChilExt;
            }
        }
    return "";
}

/// Determine offsets for all Writers, then start the write session.
/// This needs to be a threaded entry method.
void Main::cbOpen(Ck::IO::FileReadyMsg *msg)
{
    size_t nHeader;
    size_t nBytes;
    int64_t nParts;
    if(pOutput->iBinaryOut != 6) {
        nHeader = sizeof(int);
        nParts = nTotalParticles;
    }
    else {
        nHeader = FieldHeader::sizeBytes;
        if(pOutput->bFloat) {
            if(pOutput->bVector) 
                nHeader += 6*sizeof(float);
            else
                nHeader += 2*sizeof(float);
        }
        else
            nHeader += 2*sizeof(int64_t);
        if(pOutput->iTypeWriting == TYPE_GAS)
            nParts = nTotalSPH;
        else if(pOutput->iTypeWriting == TYPE_DARK)
            nParts = nTotalDark;
        else if(pOutput->iTypeWriting == TYPE_STAR)
            nParts = nTotalStar;
        }
    if(pOutput->bFloat)
        nBytes = nParts*sizeof(float);
    else if(pOutput->iBinaryOut != 6)
        nBytes = nParts*sizeof(int); // Tipsy binary does ints
    else
        nBytes = nParts*sizeof(int64_t);
    if(pOutput->bVector) 
        nBytes *= 3;
    // XXX This would be better as a parallel prefix operation       
    writeProxy[0].outputBinaryStart(*pOutput, 0, CkCallbackResumeThread());
    fIOFile = msg->file;
    Ck::IO::startSession(msg->file, nBytes + nHeader, 0,
                         CkCallback(CkIndex_Main::cbIOReady(NULL), thishandle),
                         CkCallback(CkIndex_Main::cbIOComplete(NULL), thishandle));
    delete msg;
}

/// Determine start offsets for this piece based on previous pieces.
void Writer::outputBinaryStart(OutputParams& params, int64_t nStart,
                                  const CkCallback& cb)
{
    nStartWrite = nStart;

    if(thisIndex == CkNumPes() - 1) {
        cb.send();
        return;
        }

    int64_t nMyParts;
    if(params.iBinaryOut != 6) {
        nMyParts = vMyParticles.size();
    }
    else {
        if(params.iTypeWriting == TYPE_GAS)
            nMyParts = vMySPHParticles.size();
        else if(params.iTypeWriting == TYPE_DARK)
            nMyParts = vMyParticles.size() - vMySPHParticles.size()
                - vMyStarParticles.size();
        else if(params.iTypeWriting == TYPE_STAR)
            nMyParts = vMyStarParticles.size();
        else
            CkAbort("Bad writing type.");
        }
    thisProxy[thisIndex+1].outputBinaryStart(params, nStart + nMyParts, cb);
}

/// Session is ready; write my data.
void Main::cbIOReady(Ck::IO::SessionReadyMsg *msg)
{
    writeProxy.outputBinary(msg->session, *pOutput);
    delete msg;
}

/// All IO has completed.  Close the file
void Main::cbIOComplete(CkMessage *msg)
{
    Ck::IO::close(fIOFile, CkCallback(CkIndex_Main::cbIOClosed(NULL),
                                      thishandle));
    delete msg;
}

/// File is closed.  Update header for NChilada.  Resume main program
void Main::cbIOClosed(CkMessage *msg)
{
    FILE *outfile;
    XDR xdrs;
    
    delete msg;
    
    if(pOutput->iBinaryOut != 6) {
        int iDum;
        outfile = CmiFopen((pOutput->fileName+"."+pOutput->sTipsyExt).c_str(),
                           "r+");
        CkAssert(outfile != NULL);
        xdrstdio_create(&xdrs, outfile, XDR_ENCODE);
        iDum = (int)nTotalParticles;
        xdr_int(&xdrs,&iDum);
        xdr_destroy(&xdrs);
        CmiFclose(outfile);
    }
    else {
        CkReductionMsg *msgMinMax;
        writeProxy.minmaxNCOut(*pOutput,
                               CkCallbackResumeThread((void *&)msgMinMax));
        pOutput->iTypeWriting >>= 1;  // Kludge quickly get the
                                         // current filename from
                                         // getNCNextOutput()
        
        FieldHeader fh;
        std::string sOutFile = getNCNextOutput(*pOutput);
        CkAssert(!sOutFile.empty());
        if(pOutput->iTypeWriting == TYPE_GAS)
            fh.numParticles = nTotalSPH;
        else if(pOutput->iTypeWriting == TYPE_DARK)
            fh.numParticles = nTotalDark;
        else if(pOutput->iTypeWriting == TYPE_STAR)
            fh.numParticles = nTotalStar;
        
        fh.time = pOutput->dTime;
        if(pOutput->bFloat)
            fh.code = Type2Code<float>::code;
        else
            fh.code = Type2Code<int64_t>::code;
        if(pOutput->bVector)
            fh.dimensions = 3;
        else
            fh.dimensions = 1;

        outfile = CmiFopen(sOutFile.c_str(), "r+");
        CkAssert(outfile != NULL);
        xdrstdio_create(&xdrs, outfile, XDR_ENCODE);
        xdr_template(&xdrs, &fh);
        if(pOutput->bFloat) {
            if(pOutput->bVector) {
                OrientedBox<float> bbVec = *((OrientedBox<float>*)
                                             msgMinMax->getData());
                xdr_template(&xdrs, &bbVec.lesser_corner);
                xdr_template(&xdrs, &bbVec.greater_corner);
                }
            else {
                float* minmax = (float *) msgMinMax->getData();
                xdr_float(&xdrs, &minmax[0]);
                xdr_float(&xdrs, &minmax[1]);
                }
            }
        else {
            int64_t* minmax = (int64_t *) msgMinMax->getData();
            xdr_template(&xdrs, &minmax[0]);
            xdr_template(&xdrs, &minmax[1]);
            }
        xdr_destroy(&xdrs);
        CmiFclose(outfile);
        delete msgMinMax;
        /// Continue to next particle type
        sOutFile = getNCNextOutput(*pOutput);
        if(!sOutFile.empty()) {
            Ck::IO::Options opts;
            if(param.bParaWrite) {
                if(param.nIOProcessor == 0) {
                    opts.activePEs = CkNumNodes();
                    }
                else {
                    opts.activePEs = param.nIOProcessor;
                    }
                }
            else {
                opts.activePEs = 1;
                }
            Ck::IO::open(sOutFile,
                         CkCallback(CkIndex_Main::cbOpen(0), thishandle),
                         opts);
        
            return;
            }
        }
    // Finally: resume the main program.
    cbIO.send();
}

void Writer::minmaxNCOut(OutputParams& params, const CkCallback& cb)
{
    OrientedBox<float> bbVec;
    float minmax[2] = {FLT_MAX, -FLT_MAX};
    int64_t iminmax[2] = {INT_MAX, -INT_MAX};
    params.dm = dm; // pass cooling information

    for(unsigned int i = 0; i < vMyParticles.size(); ++i) {
        if((TYPETest(&vMyParticles[i], params.iType)
            && TYPETest(&vMyParticles[i], params.iTypeWriting))
           || params.iBinaryOut != 6) {
          if(params.bFloat) {
            if(params.bVector)
                bbVec.grow(params.vValue(&vMyParticles[i]));
            else {
                float dValue = params.dValue(&vMyParticles[i]);
                if(dValue < minmax[0])
                    minmax[0] = dValue;
                if(dValue > minmax[1])
                    minmax[1] = dValue;
                }
            }
          else {
              int64_t iValue = params.iValue(&vMyParticles[i]);
              if(iValue < iminmax[0])
                  iminmax[0] = iValue;
              if(iValue > iminmax[1])
                  iminmax[1] = iValue;
              }
          }
        }
  if(params.bFloat) {
    if(params.bVector)
        contribute(sizeof(OrientedBox<float>), &bbVec,
                   growOrientedBox_float, cb);
    else
        contribute(2*sizeof(float), minmax, minmax_float, cb);
    }
  else
      contribute(2*sizeof(int64_t), iminmax, minmax_long, cb);
}
 
/// Output a Tipsy XDR binary float array file.
void Writer::outputBinary(Ck::IO::Session session, OutputParams& params)
{
    XDR xdrs;
    params.dm = dm; // pass cooling information

    if(verbosity > 3)
	CkPrintf("Writer %d: Writing output to disk\n", thisIndex);
    
    int64_t nMyParts;
    size_t nHeader;
    if(params.iBinaryOut != 6) {
        nMyParts = vMyParticles.size();
        nHeader = sizeof(int);
    }
    else {
        nHeader = FieldHeader::sizeBytes;
        if(params.bFloat) {
            if(params.bVector) 
                nHeader += 6*sizeof(float);
            else
                nHeader += 2*sizeof(float);
            }
        else
            nHeader += 2*sizeof(int64_t);
        if(params.iTypeWriting == TYPE_GAS)
            nMyParts = vMySPHParticles.size();
        else if(params.iTypeWriting == TYPE_DARK)
            nMyParts = vMyParticles.size() - vMySPHParticles.size()
                - vMyStarParticles.size();
        else if(params.iTypeWriting == TYPE_STAR)
            nMyParts = vMyStarParticles.size();
        else
            CkAbort("Bad writing type.");
        }

    size_t nBytes = nMyParts*sizeof(float);
    size_t iOffset = nStartWrite*sizeof(float);
    if(!params.bFloat) {
        if(params.iBinaryOut == 6) {
            nBytes = nMyParts*sizeof(int64_t);
            iOffset = nStartWrite*sizeof(int64_t);
            }
        else {  // Tipsy only does ints.
            nBytes = nMyParts*sizeof(int);
            iOffset = nStartWrite*sizeof(int);
            }
        }
    if(params.bVector) {
        nBytes *= 3;
        iOffset *= 3;
        }
    iOffset += nHeader;

    // CkIO Offset seems to have problems; hence the following work-around:
    if(thisIndex == 0) {
        iOffset = 0;
        nBytes += nHeader;
        }

    if(nBytes == 0)     // nothing for this piece to do.
        return;

    char *buf = new char[nBytes];
    CkAssert(nBytes < UINT_MAX); // Documentation for xdrmem_create()
                                 // specifies unsigned int.  Could be
                                 // a problem.
    xdrmem_create(&xdrs, buf, nBytes, XDR_ENCODE);

    // CkIO Offset seems to have problems; hence more work-around:
    // write a dummy header
    if(thisIndex == 0) {
        if(params.iBinaryOut != 6) {
            int iDum = 0;
            xdr_int(&xdrs, &iDum);
            }
        else {
            FieldHeader fh;
            fh.time = 0.0;
            fh.numParticles = 0;
            fh.dimensions = 0;
            if(params.bFloat)
                fh.code = Type2Code<float>::code;
            else
                fh.code = Type2Code<int64_t>::code;
            xdr_template(&xdrs, &fh);
            if(params.bFloat) {
                if(params.bVector) {
                    Vector3D<float> vMin(0.0);
                    xdr_template(&xdrs, &vMin);
                    xdr_template(&xdrs, &vMin);
                    }
                else {
                    float fMin = 0.0;
                    xdr_float(&xdrs, &fMin);
                    xdr_float(&xdrs, &fMin);
                    }
                }
            else {
                int64_t iMin = 0;
                xdr_hyper(&xdrs, &iMin);
                xdr_hyper(&xdrs, &iMin);
                }
            }
        }
    // end of CkIO Offset workaround.
    
    int nOut = 0;

    for(unsigned int i = 0; i < vMyParticles.size(); ++i) {
        if((TYPETest(&vMyParticles[i], params.iType)
            && TYPETest(&vMyParticles[i], params.iTypeWriting))
           || params.iBinaryOut != 6) {
            if(params.bFloat) {
                if(params.bVector) {
                    Vector3D<float> vec = params.vValue(&vMyParticles[i]);
                    xdr_template(&xdrs, &vec);
                    }
                else {
                    float dValue = params.dValue(&vMyParticles[i]);
                    xdr_float(&xdrs, &dValue);
                    }
                }
            else {
                if(params.iBinaryOut == 6) {
                    int64_t iValue = params.iValue(&vMyParticles[i]);
                    xdr_template(&xdrs, &iValue);
                    }
                else {  // tipsy binary array only does 32 bit ints
                    int iValue = params.iValue(&vMyParticles[i]);
                    xdr_template(&xdrs, &iValue);
                    }
                }
            nOut++;
            }
        }
    CkAssert(nOut == nMyParts);
    xdr_destroy(&xdrs);
    Ck::IO::write(session, buf, nBytes, iOffset);
    delete [] buf;
}

//// Add all of the elements of a particle family to an opened ofstream for the
//// description.xml file.  If the names vector is empty, does nothing.  Otherwise
//// appends a family tag, with sub-tags for each attribute stored in the snapshot.
void Main::NCXMLattrib(ofstream *desc, std::vector<std::string>& names,
                       std::string family)
{
    if(names.size() == 0) // Don't add a family tag if the names vector is empty.
        return;
    std::string lastStr = "";
    std::string attrib;
    *desc << "\t<family name=\"" << family << "\">" << endl;
    for(unsigned int i=0;i<names.size();i++)
    {
        attrib = names[i];
        if(attrib == "pos")
            attrib = "position";
        if(attrib == "pot")
            attrib = "potential";
        if(attrib == "vel")
            attrib = "velocity";
        if(lastStr != names[i]) {
            *desc <<  "\t\t<attribute name=\"" << attrib << "\" link=\""
                  << family << "/" << names[i] << "\"/>" << endl;
        }
        lastStr = names[i];
    }
    *desc << "\t</family>" << endl;
}

//// When writing out an NChilada snapshot, automatically generate a description.xml
//// in the snapshot directory, containing a description of the snapshot contents.
void Main::writeNCXML(const std::string filename) 
{
    // Let's use alphabetical order for the contents of each family.
    std::sort(NCgasNames.begin(), NCgasNames.end());
    std::sort(NCstarNames.begin(), NCstarNames.end());
    std::sort(NCdarkNames.begin(), NCdarkNames.end());

    ofstream xmldesc; // File handler for the XML description file
    xmldesc.open((filename+"/description.xml").c_str(), ios_base::trunc);
    
    xmldesc << "<?xml version=\"1.0\" encoding=\"iso-8859-1\"?>" << endl;
    xmldesc << "<simulation>" << endl;
    NCXMLattrib(&xmldesc, NCstarNames, "star");
    NCXMLattrib(&xmldesc, NCdarkNames, "dark");
    NCXMLattrib(&xmldesc, NCgasNames, "gas");
    xmldesc << "</simulation>" << endl;
    
    // Clear the vectors storing the family attributes for next snapshot
    NCgasNames.clear();
    NCstarNames.clear();
    NCdarkNames.clear();
    xmldesc.close();
}