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114 lines
4.4 KiB
Matlab
114 lines
4.4 KiB
Matlab
% FFT_PARTIAL apply fft only on smaller blocks (important for GPU)
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%
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% x = fft_partial(x,fft_axis,split_axis, split, inverse = false)
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%
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% Inputs:
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% **x - input array
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% **fft_axis - axis along which is performed FFT
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% **split_axis - axis along which is the array split
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%
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% *optional*
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% **split - number of blocks to split the array before FFT to save the memory
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% **inverse - if true, use ifft intead of fft
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%
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% *returns*
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% ++x fft transformed array
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%*-----------------------------------------------------------------------*
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%| |
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%| Except where otherwise noted, this work is licensed under a |
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%| Creative Commons Attribution-NonCommercial-ShareAlike 4.0 |
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%| International (CC BY-NC-SA 4.0) license. |
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%| |
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%| Copyright (c) 2017 by Paul Scherrer Institute (http://www.psi.ch) |
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%| |
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%| Author: CXS group, PSI |
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%*-----------------------------------------------------------------------*
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% You may use this code with the following provisions:
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%
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% If the code is fully or partially redistributed, or rewritten in another
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% computing language this notice should be included in the redistribution.
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%
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% If this code, or subfunctions or parts of it, is used for research in a
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% publication or if it is fully or partially rewritten for another
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% computing language the authors and institution should be acknowledged
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% in written form in the publication: “Data processing was carried out
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% using the “cSAXS matlab package” developed by the CXS group,
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% Paul Scherrer Institut, Switzerland.”
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% Variations on the latter text can be incorporated upon discussion with
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% the CXS group if needed to more specifically reflect the use of the package
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% for the published work.
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%
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% A publication that focuses on describing features, or parameters, that
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% are already existing in the code should be first discussed with the
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% authors.
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%
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% This code and subroutines are part of a continuous development, they
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% are provided “as they are” without guarantees or liability on part
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% of PSI or the authors. It is the user responsibility to ensure its
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% proper use and the correctness of the results.
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function x = fft_partial(x,fft_axis,split_axis, split, inverse)
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persistent current_gpu
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import math.*
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if nargin < 5
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inverse = false; % do inverse fft
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end
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if nargin < 4 || isempty(split)
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% auto estimation of the split
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mem_req = numel(x)*8 * log2(size(x,fft_axis));
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if isa(x,'gpuArray')
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% move directly to complex to include the expected memore requirements
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x = complex(x);
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if isempty(current_gpu) || isnan(current_gpu.AvailableMemory)
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current_gpu = gpuDevice;
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end
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split = ceil(mem_req / current_gpu.AvailableMemory);
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else
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if mem_req < 50e9
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% assume to have at least 50GB ram free ...
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split = 1;
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else
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avail_mem = utils.check_available_memory * 1e6;
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split = ceil(mem_req /avail_mem);
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end
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end
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end
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if all(split == 1)
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if inverse
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x = ifft(x,[],fft_axis);
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else
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x = fft(x,[],fft_axis);
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end
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return
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end
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% check GPU memory
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Np = size(x);
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Nps = Np;
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Nps(split_axis) = ceil(Nps(split_axis) / split);
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ind = {':', ':',':'};
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for i = 1:split
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ind{split_axis} = (1+(i-1)*Nps(split_axis)): min(Np(split_axis), i*Nps(split_axis));
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x_tmp = x(ind{:});
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if ~inverse
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x_tmp = fft(x_tmp, [], fft_axis); % avoid additonal memory assignment
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else
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x_tmp = ifft(x_tmp, [], fft_axis);
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end
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x(ind{:}) = x_tmp;
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end
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end
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