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bsxfun

Binary singleton expansion function for gpuArray

Syntax

C = bsxfun(FUN, A, B)

Description

This method of a gpuArray object is similar in behavior to the MATLAB® function bsxfun, except that the actual evaluation of the function happens on the GPU, not on the CPU.

C = bsxfun(FUN, A, B) applies the element-by-element binary operation specified by the function handle FUN to arrays A and B, with singleton expansion enabled. If A or B is a gpuArray, bsxfun moves all other required data to the GPU and performs its calculation on the GPU. The output array C is a gpuArray, whose data you can retrieve with gather.

The corresponding dimensions of A and B must be equal to each other, or equal to one. Whenever a dimension of A or B is singleton (equal to 1), bsxfun virtually replicates the array along that dimension to match the other array. In the case where a dimension of A or B is singleton and the corresponding dimension in the other array is zero, bsxfun virtually diminishes the singleton dimension to 0.

The size of the output array C is such that each dimension is the larger of the two input arrays in that dimension for nonzero size, or zero otherwise. Notice in the following code how dimensions of size 1 are scaled up or down to match the size of the corresponding dimension in the other argument:

R1 = rand(2,5,4,'gpuArray');
R2 = rand(2,1,4,3,'gpuArray');
R = bsxfun(@plus,R1,R2);
size(R)
  2     5     4     3
R1 = rand(2,2,0,4,'gpuArray');
R2 = rand(2,1,1,4,'gpuArray');
R = bsxfun(@plus,R1,R2);
size(R)
  2     2     0     4

Examples

Subtract the column means from each element of a matrix:

A = rand(8,'gpuArray');
M = bsxfun(@minus,A,mean(A));

See Also

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