MATLAB: Doesn’t MATLAB support ‘cpuArray’ for some array creation functions

Question

For example, we can create a GPU array by code:

rand(3, 'single', 'gpuArray')

Unfortunately, this code will fail if it is run on a PC without a CUDA graphics card. If we can pass 'cpuArray' to rand, we can easily write a MATLAB program for both CPU and GPU computings. E.g.,

 useGpu = 0
 if(useGpu)
    arrayType = 'gpuArray';
 else
    arrayType = 'cpuArray';
 end
 % The program ...
 A = rand(3, 'single', arrayType);
 B = rand(3, 'single', arrayType);
 C = A*B;

(Unfortunately, this example doesn't work for current MATLAB…)

Otherwise, we have to write this code:

 useGpu = 0
 if(useGpu)
     A = rand(3, 'single', 'gpuArray');
     B = rand(3, 'single', 'gpuArray');
 else
     A = rand(3, 'single');
     B = rand(3, 'single');
 end
 C = A*B;

Could MathWorks add 'cpuArray' to most array creation functions in the future?

Answer 1

Another workaround is to use a cell array.

if useGpu
  arg = {'gpuArray'};
else
  arg = {};
end
A = rand(3, 'single', arg{:});

The {:} syntax converts arg into a comma-separated list.