(Solved) : Global Void Sobelgpushared Float Image Int Height Int Width Float Xmatrix Float Ymatrix Fl Q29663235 . . .
__global__
void SobelGPUShared(float *image, int height, int width, float*x_matrix,
float *y_matrix, float *output) {
extern __shared__ float arr[];
int i = blockIdx.x*blockDim.x+threadIdx.x;
int j = blockIdx.y*blockDim.y+threadIdx.y;
//arr[i*j] = image[i*j];
if(i < height && j < width)
{
float x_grad=0;
x_grad += x_matrix[0 * MATRIX_DIM + 0] *
GetValidPixelValue(image, height, width, i – 1, j – 1);
x_grad += x_matrix[0 * MATRIX_DIM + 2] *
GetValidPixelValue(image, height, width, i – 1, j + 1);
x_grad += x_matrix[1 * MATRIX_DIM + 0] *
GetValidPixelValue(image, height, width, i, j – 1);
x_grad += x_matrix[1 * MATRIX_DIM + 2] *
GetValidPixelValue(image, height, width, i, j + 1);
x_grad += x_matrix[2 * MATRIX_DIM + 0] *
GetValidPixelValue(image, height, width, i + 1, j – 1);
x_grad += x_matrix[2 * MATRIX_DIM + 2] *
GetValidPixelValue(image, height, width, i + 1, j + 1);
__syncthreads();
float y_grad = 0;
y_grad += y_matrix[0 * MATRIX_DIM + 0] *
GetValidPixelValue(image, height, width, i – 1, j – 1);
y_grad += y_matrix[0 * MATRIX_DIM + 1] *
GetValidPixelValue(image, height, width, i – 1, j);
y_grad += y_matrix[0 * MATRIX_DIM + 2] *
GetValidPixelValue(image, height, width, i – 1, j + 1);
y_grad += y_matrix[2 * MATRIX_DIM + 0] *
GetValidPixelValue(image, height, width, i + 1, j – 1);
y_grad += y_matrix[2 * MATRIX_DIM + 1] *
GetValidPixelValue(image, height, width, i + 1, j);
y_grad += y_matrix[2 * MATRIX_DIM + 2] *
GetValidPixelValue(image, height, width, i + 1, j + 1);
__syncthreads();
float magnitude =
sqrt(x_grad / 8 * x_grad / 8 +
y_grad / 8 * y_grad / 8); // normalize gradients by dividing by8
if (magnitude > 1) { // clamp to 1
output[i * width + j] = 1;
} else if (magnitude > THRESHOLD) {
output[i * width + j] = magnitude;
} else {
output[i * width + j] = 0;
}
// Implement this function, define a GPU kernel above it
}
}
Given this Cuda C++ function, how can you divide the image arrayinto tiles that will fit in shared memory? You only have to worryabout the parallelization part and not the actual sobel filtercalculations that are being done.
Expert Answer
Answer to Global Void Sobelgpushared Float Image Int Height Int Width Float Xmatrix Float Ymatrix Fl Q29663235 . . .
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