Problem with "shared" dinamic arrays

Byte-Welt - Projekte / Projects JCuda
1

Hello!
I write kernel and I have one problem with “shared” dinamic arraysl.

__global__ void calculate(int size, int N, float* a){
	__shared__ float arr[N*2];
//somework
}```

It returns error:
Exception in thread "main" java.io.IOException: Could not create .ptx file: fft-simple.cu
fft-simple.cu(3): error: expression must have a constant value

Please, help me. How I can create this array? The value of N defines in Java Code.
2

Hello

You can add this as a constant by passing it as a ‘defined’ value to the NVCC (or the KernelLauncher, which you may be using) - For example, you may call this…

k = KernelLauncher.create(fileName, functionName, true, "-DMY_SIZE=123"); // Add -D... parameter here

and then use MY_SIZE in the kernel like this:

extern "C"
__global__ void calculate(int size, float* a){
    __shared__ float arr[MY_SIZE*2];
...

Just from the tip of my head, if it does not work, I’ll have another look at this any possibly post an example.

bye

3

Thank you very much, Marco!
It resolved this issue. And you teached me how to create constants :wink:

4

You can also create constants with the “const” or “constant” keywords, but you cannot declare arrays with them!