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March 19th, 2017, 03:00 PM
#1
Parallalization of matrix multiply error
I'm tried to multiply 1000x1000 matrixes with segments. But I get an error..
Code:
#include "stdafx.h"
#include <Windows.h>
#include <stdio.h>
#include <iostream>
#include <process.h>
#include <stdlib.h>
#include <math.h>
#include <chrono>
volatile int str = 0;
const int size = 100;
const int BLM = 25;
int **A;//Matrix A
int **B;//Matrix B
int **C;//Output Matrix C
//int matriscarp(int, int);
//void matrisAtama();
//void destruct();
using namespace std;
void matrisAtama(){
//assigning first dimension
A = new int*[size];
//Assign second dimension
for (int i = 0; i < size; i++)
{
A[i] = new int[size];
}
//assigning first dimension
B = new int*[size];
//Assign second dimension
for (int i = 0; i < size; i++)
{
B[i] = new int[size];
}
//assigning first dimension
C = new int*[size];
//Assign second dimension
for (int i = 0; i < size; i++)
{
C[i] = new int[size];
}
int l = 1, u = 1;
for (int i = 0; i < size; i++)
for (int j = 0; j < size; j++)
{
l++;
u++;
l = l % 9;
u = u % 9;
A[i][j] = l;
B[i][j] = u;
}
}
void destruct(){
//delete the dynamic memory of A
for (int i = 0; i < size; i++)
{
delete[] A[i];
}
delete[] A;
//delete the dynamic memory of B
for (int i = 0; i < size; i++)
{
delete[] B[i];
}
delete[] B;
//delete the dynamic memory of C
for (int i = 0; i < size; i++)
{
delete[] C[i];
}
delete[] C;
}
int matriscarp(int n, int p){
//auto BslTimer = chrono::high_resolution_clock::now();
for (int i = 0; i < size; i++)
for (int j = 0; j < size; j++)
{
C[i][j] = 0; //initializing c to zero
}
for (int i = n; i < p; i++){
cout << endl;
for (int j = 0; j < size; j++)
{
for (int k = 0; k < size; k++){
C[j][i] += A[j][k] * B[k][i];
}
}
}
for (int i = 0; i < size; i++){
for (int j = 0; j < size; j++)
{
cout << C[i][j] << " ";
}
}
/*auto BtsTimer = std::chrono::high_resolution_clock::now();
auto sure = BtsTimer - BslTimer;
printf("Total duration %5d \n", chrono::duration_cast<std::chrono::milliseconds>(sure).count());*/
return 1;
}
unsigned int __stdcall fFonk(void*){
auto BslTimer = chrono::high_resolution_clock::now(); // zamanı başlat
while (str < size) {
int t_str;
t_str = str; // şimdiki değerini al
str += BLM; //ve sıradaki 250 taneyi coz
matriscarp(t_str, t_str+BLM);
// bulunan sayıları ekrana basabilirsiniz
//printf("Thread no %7d sayi = %8d asal mi = %s\n", GetCurrentThreadId(), j, s);
// her thread 200'li blokları hesaplar
// her thread kendi süresini yazar
auto BtsTimer = std::chrono::high_resolution_clock::now(); // bittikten sonra zamani oku
auto sure = BtsTimer - BslTimer; /// farki hesapla
printf("Toplam sure %5d ms\n", chrono::duration_cast<std::chrono::milliseconds>(sure).count());
return 0;
}
}
int main(int argc, char* argv[]){
HANDLE hndl1, hndl2, hndl3, hndl4;
matrisAtama();
hndl1 = (HANDLE)_beginthreadex(0, 0, &fFonk, (void*)0, 0, 0);
hndl2 = (HANDLE)_beginthreadex(0, 0, &fFonk, (void*)0, 0, 0);
hndl3 = (HANDLE)_beginthreadex(0, 0, &fFonk, (void*)0, 0, 0);
hndl4 = (HANDLE)_beginthreadex(0, 0, &fFonk, (void*)0, 0, 0);
WaitForSingleObject(hndl1, INFINITE);
WaitForSingleObject(hndl2, INFINITE);
WaitForSingleObject(hndl3, INFINITE);
WaitForSingleObject(hndl4, INFINITE);
CloseHandle(hndl1);
CloseHandle(hndl2);
CloseHandle(hndl3);
CloseHandle(hndl4);
destruct();
getchar();
return 0;
}
This is the error i got: Warning 1 warning C4715: 'fFonk' : not all control paths return a value c:\users\consium nullum\documents\visual studio 2013\projects\d3d11_chess\d3d11_chess\xaa\xaa\xaa.cpp 137 1 xaa
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March 19th, 2017, 03:17 PM
#2
Re: Parallalization of matrix multiply error
The warning is correct. If the function is indented
Code:
unsigned int __stdcall fFonk(void*)
{
auto BslTimer = chrono::high_resolution_clock::now(); // zamanı başlat
while (str < size) {
int t_str;
t_str = str; // şimdiki değerini al
str += BLM; //ve sıradaki 250 taneyi coz
matriscarp(t_str, t_str+BLM);
// bulunan sayıları ekrana basabilirsiniz
//printf("Thread no %7d sayi = %8d asal mi = %s\n", GetCurrentThreadId(), j, s);
// her thread 200'li blokları hesaplar
// her thread kendi süresini yazar
auto BtsTimer = std::chrono::high_resolution_clock::now(); // bittikten sonra zamani oku
auto sure = BtsTimer - BslTimer; /// farki hesapla
printf("Toplam sure %5d ms\n", chrono::duration_cast<std::chrono::milliseconds>(sure).count());
return 0;
}
//missing return value here
}
When the while loop terminates when str >= size, the function does not return a value. Should the return 0 statement be outside of the while loop?
All advice is offered in good faith only. All my code is tested (unless stated explicitly otherwise) with the latest version of Microsoft Visual Studio (using the supported features of the latest standard) and is offered as examples only - not as production quality. I cannot offer advice regarding any other c/c++ compiler/IDE or incompatibilities with VS. You are ultimately responsible for the effects of your programs and the integrity of the machines they run on. Anything I post, code snippets, advice, etc is licensed as Public Domain https://creativecommons.org/publicdomain/zero/1.0/ and can be used without reference or acknowledgement. Also note that I only provide advice and guidance via the forums - and not via private messages!
C++23 Compiler: Microsoft VS2022 (17.6.5)
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