void main()
{
float a[10][10];
int i,j,order;
printf("\n\nEnter order of matrix :");
scanf("%d",&order);
printf("\nEnter the square matrix :\n");
for(i=0;i<order;i++)
for(j=0;j<order;j++)
scanf("%f",&a[i][j]);
printf("Determinent Value :%f\n",detrm(a,order));
}
double detrm( double a[DIM][DIM], double k )
{
double s = 1, det = 0, b[DIM][DIM];
int i, j, m, n, c;
if ( k == 1 )
{
return ( a[ 0 ][ 0 ] );
}
else
{
det = 0;
for ( c = 0;c < k;c++ )
{
m = 0;
n = 0;
for ( i = 0;i < k;i++ )
{
for ( j = 0;j < k;j++ )
{
b[ i ][ j ] = 0;
if ( i != 0 && j != c )
{
b[ m ][ n ] = a[ i ][ j ];
if ( n < k-2 )
n++;
else
{
n = 0;
m++;
}
}
}
}
det = det + s * ( a[ 0 ][ c ] * detrm( b, k-1 ) );
s = -1 * s;
}
}
return ( det );
}
//---------------------------------------------------------
void CGrid_IMCORR::kvert(std::vector<std::vector<float> >& V)
{
const int k = (int)V[0].size();
float b[25][25];
for ( int i = 0;i < k;i++ )
{
for (int j = 0;j < k;j++ )
{
b[ i ][ j ] = V[ i ][ j ];
}
}
float d = detrm( b, (float)k );
if ( d != 0 )
cofact( b, (float)k, V);
return;
}
//---------------------------------------------------------
float CGrid_IMCORR::detrm( float a[ 25 ][ 25 ], float k )
{
float s = 1, det = 0, b[ 25 ][ 25 ];
int i, j, m, n, c;
if ( k == 1 )
{
return ( a[ 0 ][ 0 ] );
}
else
{
det = 0;
for ( c = 0;c < k;c++ )
{
m = 0;
n = 0;
for ( i = 0;i < k;i++ )
{
for ( j = 0;j < k;j++ )
{
b[ i ][ j ] = 0;
if ( i != 0 && j != c )
{
b[ m ][ n ] = a[ i ][ j ];
if ( n < ( k-2 ) )
n++;
else
{
n = 0;
m++;
}
}
}
}
det = det + s * ( a[ 0 ][ c ] * detrm( b, k-1 ) );
s = -1 * s;
}
}
return ( det );
}
//---------------------------------------------------------
void CGrid_IMCORR::cofact( float num[ 25 ][ 25 ], float f, std::vector<std::vector<float> >& INV )
{
float b[ 25 ][ 25 ], fac[ 25 ][ 25 ];
int p, q, m, n, i, j;
for ( q = 0;q < f;q++ )
{
for ( p = 0;p < f;p++ )
{
m = 0;
n = 0;
for ( i = 0;i < f;i++ )
{
for ( j = 0;j < f;j++ )
{
b[ i ][ j ] = 0;
if ( i != q && j != p )
{
b[ m ][ n ] = num[ i ][ j ];
if ( n < ( f-2.0 ) )
n++;
else
{
n = 0;
m++;
}
}
}
}
fac[ q ][ p ] = (float)(pow( -1.0, (q + p) ) * detrm( b, (f-1) ));
}
}
trans( num, fac, f, INV );
return;
}
//---------------------------------------------------------
void CGrid_IMCORR::trans( float num[ 25 ][ 25 ], float fac[ 25 ][ 25 ], float r , std::vector<std::vector<float> >& INV)
{
int i, j;
float b[ 25 ][ 25 ], inv[ 25 ][ 25 ], d;
for ( i = 0;i < r;i++ )
{
for ( j = 0;j < r;j++ )
{
b[ i ][ j ] = fac[ j ][ i ];
}
}
d = detrm( num, r );
inv[ i ][ j ] = 0;
for ( i = 0;i < r;i++ )
{
for ( j = 0;j < r;j++ )
{
inv[ i ][ j ] = b[ i ][ j ] / d;
}
}
INV.resize((int)r);
for (int ii = 0; ii < r; ii++)
{
INV[ii].resize((int)r);
}
for ( i = 0;i < r;i++ )
{
for ( j = 0;j < r;j++ )
{
INV[ i ][ j ] = inv[ i ][ j ];
}
}
return;
}
float detrm(float a[10][10],int n)
{
float b[10][10],sum=0;
int i,j,k,x,u=1;
if(n==1)
return a[0][0];
for(i=0;i<n;i++)
{
for(j=0;j<n-1;j++)
{
x=0;
for(k=0;k<n-1;k++)
{
if(k==i)
x++;
b[j][k]=a[j+1][x+k];
}
}
sum+=u*a[0][i]*detrm(b,n-1);
u*=-1;
}
return sum;
}
