User`s guide

Run MEX-Functions Containing CUDA Code

9-33

Compile a GPU MEX-File

When you have set up the options file, use the mex command in MATLAB to compile

a MEX-file containing the CUDA code. You can compile the example file using the

command:

mex -largeArrayDims mexGPUExample.cu

The -largeArrayDims option is required to ensure that 64-bit values for array

dimensions are passed to the MEX API.

Run the Resulting MEX-Functions

The MEX-function in this example multiplies every element in the input array by 2 to get

the values in the output array. To test it, start with a gpuArray in which every element is

x = ones(4,4,'gpuArray');

y = mexGPUExample(x)

y =

2 2 2 2

Both the input and output arrays are gpuArray objects:

disp(['class(x) = ',class(x),', class(y) = ',class(y)])

class(x) = gpuArray, class(y) = gpuArray

Comparison to a CUDA Kernel

Parallel Computing Toolbox also supports CUDAKernel objects that can be used to

integrate CUDA code with MATLAB. Consider the following when choosing the MEX-file

approach versus the CUDAKernel approach:

• MEX-files can interact with host-side libraries, such as the NVIDIA Performance

Primitives (NPP) or CUFFT libraries, and can also contain calls from the host to

functions in the CUDA runtime library.