function y = zeroSolve(P, b)%%  Overload matrix solves for a psfPrec object using%  zero boundary conditions.%%  J. Nagy & K. Lee  3/7/02PSFs = P.matdata;nregions = size(PSFs);imsize=size(b);if length(imsize) == 1  imsize = [imsize, 1, 1];elseif length(imsize) == 2  imsize = [imsize, 1];endif length(nregions) == 1  nregions = [nregions,1,1];elseif length(nregions) == 2  nregions = [nregions,1];endrsize = ceil(imsize ./ nregions);%%  Coding the rest of this will be easier if all of the image subregions%  have the same dimensions.  If it's not, we pad with a few zeros to make%  it so ...%padsize1 = rsize .* nregions - imsize;if any( padsize1 < 0 )  error('Something is wrong here ...')endb = padarray(b, padsize1, 'post');%%  Now we get information about beginning and ending indices of subregions%  so we can "get" subregions correctly ...%[RIidx, RJidx, RKidx] = region_indices( nregions, rsize );y = zeros(size(b));if (P.transpose)  for k = 1:size(PSFs,3)    for i = 1:size(PSFs,1)      for j = 1:size(PSFs,2)        bsub = b(RIidx(i,1):RIidx(i,2), RJidx(j,1):RJidx(j,2), RKidx(k,1):RKidx(k,2));        %M=PSFs;        M = PSFs{i,j,k};        y(RIidx(i,1):RIidx(i,2), RJidx(j,1):RJidx(j,2), RKidx(k,1):RKidx(k,2)) = ...               real( ifftn( conj(M) .* fftn(bsub) ) );       end    end  endelse  for k = 1:size(PSFs,3)    for i = 1:size(PSFs,1)      for j = 1:size(PSFs,2)        bsub = b(RIidx(i,1):RIidx(i,2), RJidx(j,1):RJidx(j,2), RKidx(k,1):RKidx(k,2));        %M=PSFs;        M = PSFs{i,j,k};        y(RIidx(i,1):RIidx(i,2), RJidx(j,1):RJidx(j,2), RKidx(k,1):RKidx(k,2)) = ...               real( ifftn( M .* fftn(bsub) ) );       end    end  endendy = y(1:imsize(1), 1:imsize(2), 1:imsize(3));