make passive grid calls get_plasma_extrema for incorrect number of channels #290

If you want to calculate passive signal of NPA or FIDA only, it callest get_plasma_extrema with r0_arr and v0_arr of size spec_chords%nchan+npa_chords%nchan. The positions corresponding to diagnostic, that you did not want to count are strange numbers (usually 0, but also nan), leading to code freezing.

Suggested solution:

call get_plasma_extrema with positions of considered diagnostics only:

!! Next consider passive diagnostic extrema relative to the plasma
if((inputs%calc_pfida.gt.0).and.(inputs%calc_pnpa.gt.0)) then
do i=1,(spec_chords%nchan)
r0_arr(:,i) = spec_chords%los(i)%lens_uvw
v0_arr(:,i) = spec_chords%los(i)%axis_uvw
enddo
do i=1, npa_chords%nchan
call xyz_to_uvw(npa_chords%det(i)%detector%origin, r0_arr(:,i+spec_chords%nchan))
xyz_axis = npa_chords%det(i)%detector%basis
v0_arr(:,i+spec_chords%nchan) = matmul(beam_grid%basis, xyz_axis(:,3))
enddo
call get_plasma_extrema(r0_arr,v0_arr,extrema,xarr_beam_grid,yarr_beam_grid)
else if(inputs%calc_pfida.gt.0) then
do i=1, spec_chords%nchan
r0_arr(:,i) = spec_chords%los(i)%lens_uvw
v0_arr(:,i) = spec_chords%los(i)%axis_uvw
enddo
call get_plasma_extrema(r0_arr(:,:spec_chords%nchan),v0_arr(:,:spec_chords%nchan),extrema,xarr_beam_grid,yarr_beam_grid)
else !pnpa>=1 case
do i=1, npa_chords%nchan
call xyz_to_uvw(npa_chords%det(i)%detector%origin, r0_arr(:,i))
xyz_axis = npa_chords%det(i)%detector%basis
v0_arr(:,i) = matmul(beam_grid%basis, xyz_axis(:,3))
enddo
call get_plasma_extrema(r0_arr(:,:npa_chords%nchan),v0_arr(:,:npa_chords%nchan),extrema,xarr_beam_grid,yarr_beam_grid)
endif