void cramer3(double *px,double *py,double *pz,
double a11,double a12,double a13,
double a21,double a22,double a23,
double a31,double a32,double a33,
double b1, double b2, double b3 )
{ double det;
*px = sarrus(b1 ,a12,a13, b2 ,a22,a23, b3 ,a32,a33);
*py = sarrus(a11,b1 ,a13, a21,b2 ,a23, a31,b3 ,a33);
*pz = sarrus(a11,a12,b1 , a21,a22,b2 , a31,a32,b3 );
det = sarrus(a11,a12,a13, a21,a22,a23, a31,a32,a33);
if(det != 0.0){ *px/=det;*py/=det;*pz/=det;}
}
/* This function calculates the determinant of a matrix using
* the Laplace expansion
* returns -1 if the matrix isn't square */
double determinant_laplace(struct matrix m)
{
if(m.rows!=m.columns)
{
printf("Can't calculate determinant\n");
printf("Input matrix isn't square\n");
return -1;
}
if(m.rows==2||m.rows==3)
return sarrus(m);
unsigned int i;
double det=0;
for (i = 0; i < m.columns; i++)
{
if(m.mat[0][i]!=0)
if(i%2==0)
det+=m.mat[0][i]*determinant_laplace(minor_matrix(m,0,i));
else
det-=m.mat[0][i]*determinant_laplace(minor_matrix(m,0,i));
}
return det;
}
