remove obsolete workaround in astraFDK.m to improve performance

functions/tomography/astraWrappers/astraFDK.m

@@ -39,10 +39,9 @@ function vol = astraFDK(projs,tomoAngles,z01,z02,dx,settings)
 % numSlices : Default = 1
 %     Number of slices to be reconstructed
 % offset : Default = 0
-%     Offset of the reconstructed volume to the central slice of detector. If the
-%     entire volume is reconstructed, the offset should be 0. Otherwise it can be
-%     used to reconstruct single tomographic slcies at different heights of the
-%     object.
+%     Offset of the reconstructed volume to the central slice of detector.
+%     Can be used to compensate a shift between source and detector height or
+%     to reconstruct a subvolume.
 % iradonOrientation : Default = true
 %     Orientation of the returned volume. iradonOrientation = true returns
 %     projections with the same orientation as Matlab's iradon function.
@@ -156,35 +155,6 @@ if ~isreal(projs)
 end
 
 
-% WORKAROUND: Astra's FDK algorithm tends to cause crashes in MATLAB if the reconstructed volume
-% is too large. In this case, the reconstruction has to be sequentially performed on smaller chunks
-MAX_VOLUME_SIZE = 256*1024*1024;    % Maximum 1 Gigabyte of volume data reconstructed in one chunk
-numChunks = ceil(settings.outputSize.^2 * settings.numSlices / MAX_VOLUME_SIZE);
-if numChunks > 1
-    vol = zeros([settings.outputSize*[1,1], settings.numSlices], 'single');
-    slicesPerChunk = ceil(settings.numSlices/numChunks);
-    
-    % convert input to single precision to avoid copying in each call of astraFDK in the loop below
-    if ~isa(projs, 'single')
-        projs = single(projs);
-    end
-
-    for chunkIdx = 1:numChunks
-        firstSlice = 1+(chunkIdx-1)*slicesPerChunk;
-        lastSlice = min(firstSlice+slicesPerChunk-1, settings.numSlices);
-        midSlice = 0.5*(firstSlice+lastSlice);
-
-        settingsChunk = settings;
-        settingsChunk.numSlices = lastSlice - firstSlice + 1;
-        settingsChunk.offset = settings.offset + (midSlice-1) - (settings.numSlices-1)/2;
-        vol(:,:,firstSlice:lastSlice) = astraFDK(projs, tomoAngles, z01, z02, dx, settingsChunk);
-    end
-
-    return;
-end
-
-
-%% here it starts
 % create volume geometry
 % input:
 % size of volume in y, size of volume in x, size of volume in z,