Exercises_MarkusSchmidt/sheet3/7/main.cpp
Markus Schmidt 56614805cf sheet3
2025-11-12 00:14:00 +01:00

68 lines
1.2 KiB
C++

#include <cassert>
#include <chrono> // timing
#include <cmath> // sqrt()
#include <cstdlib> // atoi()
#include <cstring> // strncmp()
#include <ctime>
#include <iostream>
#include <sstream>
#include <vector>
#include <lapacke.h>
using namespace std;
using namespace std::chrono; // timing
int main()
{
unsigned int n= 10;
unsigned int nhrs = 1;
vector<double> M(n*n,4.0);
for(unsigned int i=0; i<n; i++)
{
for(unsigned int j=0; j<n; j++)
{
if(i!=j)
{
double diff = i-j;
M[i*n+j] = 1.0/(diff*diff);
}
}
}
vector<int> ipiv(n); //pivots
LAPACKE_dgetrf(LAPACK_ROW_MAJOR,n,n, M.data(),n,ipiv.data()); //M=PLU
unsigned int runtimes[] = {1,2,4,8,16,32};
for(unsigned int i=0; i < 6;i++)
{
nhrs = runtimes[i];
vector<double> b(n*nhrs,0.0);
for (unsigned int j=0; j<n; j++)
{
for (unsigned int k=0; k<nhrs; k++)
{
b[j*nhrs+k] = j*nhrs+k;
}
}
LAPACKE_dgetrs(LAPACK_ROW_MAJOR,'N',n,nhrs,M.data(),n,ipiv.data(),b.data(),nhrs);
}
return 0;
}