sigmoid.cu

__global__ void kSigmoid(float const *input, float *output) {
    /*  Computes the value of the sigmoid function f(x) = 1/(1 + e^-x).
     Inputs:
     input: array
     output: array, the results of the computation are to be stored here
    */

    const int id = blockIdx.x * blockDim.x + threadIdx.x;

    output[id] = 1.0 / (1.0 + std::exp(-input[id]));
}

__device__ void dSigmoid(float const *input, float *output, const int height, const int width){
	kSigmoid <<< height, width >>> (input, output);
	cudaDeviceSynchronize();
}