How can I raise a matrix to the nth power in C? Here is what I have so far. wher

Question

How can I raise a matrix to the nth power in C?

Here is what I have so far.

where:

dim = dimensions of the matrix

powernum = the power the matrix is being raised to.

matrix = the matrix.

int matrixAns[dim][dim];

int i,c,d,k;

int sum = 0;

for (i = 0; i < powernum; i++)
{
for ( c = 0 ; c < dim ; c++ )
{
for (d = 0 ; d < dim ; d++ )
{
for ( k = 0 ; k < dim ; k++ )
{
sum += matrix[c][k]*matrix[k][d];
}
matrixAns[c][d] = sum;
sum = 0;
}
}
  
for ( c = 0 ; c < dim; c++ ) {
for ( d = 0 ; d < dim ; d++ ) {
matrix[c][d] = matrixAns[c][d];
matrixAns[c][d] = 0;
}
}
}

Please help me, thank you.

Explanation / Answer

#include <stdio.h>

int a[10][10],c[10][10],r;

void mul()   //to multiply 2 matrices
{
   int b[10][10],i,j,k;
   for(i=0;i < r;i++)
   {
       for(j=0;j < r;j++)
       {
           b[i][j]=0;
           for(k=0;k < r;k++)
           b[i][j]=b[i][j]+a[i][k]*c[k][j]; //to multiply a and c
       }
      
   }
   for(i=0;i < r;i++)
   {
       for(j=0;j < r;j++)
       c[i][j]=b[i][j];   //assign value of c as a*c
   }
}

int main()
{
   int i,j,n;
   scanf("%d",&r); //order of matrix
   for(i=0;i < r;i++)
   {
       for(j=0;j < r;j++)
       {
           scanf("%d",&a[i][j]); //inputting the matrix
           if(i==j)   //assigning c as identity matrix
           c[i][j]=1;
           else
           c[i][j]=0;
       }
   }
   scanf("%d",&n); //inputting power
   for(i=0;i < n;i++)
   mul();    //multiplying the matrix n time
   for(i=0;i < r;i++)
   {
       for(j=0;j < r;j++)
       printf(" %d",c[i][j]); //printing answer
       printf(" ");
   }
}

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