#include<stdio.h>
#include<math.h>
#define N 2
/* multiply 2 square matrices a and b and return c=a*b */
int matmult(float a[N][N], float b[N][N], float c[N][N])
{ int i,j,k;
for(i=0;i<N;i++)
for(j=0;j<N;j++)
{ c[i][j]=0;
for(k=0;k<N;k++)
c[i][j] = c[i][j]+a[i][k]*b[k][j];
};
return 0;
};
/* return c = a^k */
int matpow(float a[N][N], int k, float c[N][N])
{
int i,j,i1;
float b[N][N];
if(k<1){
printf("ERROR: k<1");
return -1;
}
for(i=0;i<N;i++) for(j=0;j<N;j++) b[i][j]=a[i][j];
for(i=1;i<k;i++)
{ matmult(a,b,c);
for(i1=0;i1<N;i1++) for(j=0;j<N;j++) b[i1][j]=c[i1][j];
};
return 0;
}
int matprintsquare(float a[N][N])
{ int i,j;
for(i=0;i<N;i++)
{for(j=0;j<N;j++)
printf("%f ",a[i][j]);
printf("\n");
};
return 0;
};
int main(void)
{ float a[N][N];
float c[N][N];
int i,j;
/* random seed */
srand(time(0));
/* initialize a[][] with random floats in [0;1] */
for(i=0;i<N;i++)
for(j=0;j<N;j++)
a[i][j] = i+j; /*(float)rand()/(float)RAND_MAX;*/
matprintsquare(a);
matpow(a, 3, c);
printf("\n");
matprintsquare(c);
return 0;
}
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