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→Array Processing
Blaise Barney introduced Parallel Computing https://computing.llnl.gov/tutorials/parallel_comp/
Array processing could become one of the parallel example, which "demonstrates calculations on 2-dimensional array elements; a function is evaluated on each array element."
Here is my source code
{| class="wikitable mw-collapsible mw-collapsed"
! arrayProcessing.cpp
|-
|
<pre>
// arrayProcessing.cpp
// Array processing implement parallel solution
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <ctime>
void init(float** randomValue, int n) {
//std::srand(std::time(nullptr));
float f = 1.0f / RAND_MAX;
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
randomValue[i][j] = std::rand() * f;
}
void multiply(float** a, float** b, float** c, int n) {
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++) {
float sum = 0.0f;
for (int k = 0; k < n; k++)
sum += a[i][k] * b[k][j];
c[i][j] = sum;
if(n <= 10){
std::cout << "array c[" << i << "," << j << "]: " << c[i][j] << std::endl;
}
}
}
int main(int argc, char* argv[]) {
// interpret command-line argument
if (argc != 2) {
std::cerr << argv[0] << ": invalid number of arguments\n";
std::cerr << "Usage: " << argv[0] << " size_of_matrices\n";
return 1;
}
int n = std::atoi(argv[1]); // size of matrices
float** a = new float*[n];
for (int i = 0; i < n; i++)
a[i] = new float[n];
float** b = new float*[n];
for (int i = 0; i < n; i++)
b[i] = new float[n];
float** c = new float*[n];
for (int i = 0; i < n; i++)
c[i] = new float[n];
std::srand(std::time(nullptr));
init(a, n);
init(b, n);
multiply(a, b, c, n);
for (int i = 0; i < n; i++)
delete [] a[i];
delete [] a;
for (int i = 0; i < n; i++)
delete [] b[i];
delete [] b;
for (int i = 0; i < n; i++)
delete [] c[i];
delete [] c;
}
</pre>
|}
Standard random method is used to initialize a 2-dimentional array. The purpose of this program is to perform a 2-dimension array calculation, which is a matrix-matrix multiplication in this example.