[Need an advice] [Kernel] Initialize array Does "int myArray [7] = {0};" work ?

Accelerated Computing CUDA CUDA Programming and Performance
#1

Hello all.

This is my first post here.

I’m a beginner with CUDA and I need an advice regarding Array Initialization. Let’s take an short example :

__global__ kernel_1 (bool* Value)

{

int offset = blockDim.x * blockIdx.x + threadIdx.x;

int myArray [7] = {0} ;

if( myArray[0] == 0)

Value[offset] = true;

else

Value[offset] = false;

}

If I launch the kernel, and then retrieve the booleans, 99% of the time, myArray[0] is different from 0.

My question is : Is it normal or did I make a mistake ?

Thank you in advance.

Alice.

#2

Looking at the .ptx file generated (after inserting the missing [font=“Courier New”]void[/font] declaration, the compiler optimizes this to

__global__ void kernel_1 (bool* Value)

{

    int offset = blockDim.x * blockIdx.x + threadIdx.x;

    Value[offset] = true;

}

so there should be no doubt that [font=“Courier New”]Value[/font] gets set to [font=“Courier New”]true[/font] if the kernel executes at all. Do you check return codes for errors?

#3

I’m sorry for the missing ‘void’, I have re-written the code directly in the post.

‘cudaMemCpy’ returns 0 when I execute the program…