#ifndef MSP_LINAL_SQUAREMATRIX_H_
#define MSP_LINAL_SQUAREMATRIX_H_
+#include <stdexcept>
#include "matrix.h"
namespace Msp {
namespace LinAl {
+class not_invertible: public std::domain_error
+{
+public:
+ not_invertible(): domain_error(std::string()) { }
+ virtual ~not_invertible() throw() { }
+};
+
template<typename T, unsigned S>
class SquareMatrix: public Matrix<T, S, S>
{
public:
- SquareMatrix();
- SquareMatrix(const T *);
+ SquareMatrix() { }
+ SquareMatrix(const T *d): Matrix<T, S, S>(d) { }
template<typename U>
- SquareMatrix(const Matrix<U, S, S> &);
+ SquareMatrix(const Matrix<U, S, S> &m): Matrix<T, S, S>(m) { }
+
static SquareMatrix identity();
SquareMatrix &operator*=(const SquareMatrix &);
- void invert();
+ SquareMatrix &invert();
};
+template<typename T, unsigned S>
+inline SquareMatrix<T, S> SquareMatrix<T, S>::identity()
+{
+ SquareMatrix<T, S> m;
+ for(unsigned i=0; i<S; ++i)
+ m(i, i) = T(1);
+ return m;
+}
+
+template<typename T, unsigned S>
+SquareMatrix<T, S> &SquareMatrix<T, S>::operator*=(const SquareMatrix<T, S> &m)
+{
+ Matrix<T, S, S>::operator*=(m);
+ return *this;
+}
+
+template<typename T, unsigned S>
+SquareMatrix<T, S> &SquareMatrix<T, S>::invert()
+{
+ SquareMatrix<T, S> r = identity();
+ for(unsigned i=0; i<S; ++i)
+ {
+ if(this->element(i, i)==T(0))
+ {
+ unsigned pivot = i;
+ for(unsigned j=i+1; j<S; ++j)
+ if(abs(this->element(j, i))>abs(this->element(pivot, i)))
+ pivot = j;
+
+ if(pivot==i)
+ throw not_invertible();
+
+ this->exchange_rows(i, pivot);
+ r.exchange_rows(i, pivot);
+ }
+
+ for(unsigned j=i+1; j<S; ++j)
+ {
+ T a = -this->element(j, i)/this->element(i, i);
+ this->add_row(i, j, a);
+ r.add_row(i, j, a);
+ }
+
+ T a = T(1)/this->element(i, i);
+ this->multiply_row(i, a);
+ r.multiply_row(i, a);
+ }
+
+ for(unsigned i=S; i-->0; )
+ for(unsigned j=i; j-->0; )
+ r.add_row(i, j, -this->element(j, i));
+
+ return *this = r;
+}
+
+template<typename T, unsigned S>
+inline SquareMatrix<T, S> invert(const SquareMatrix<T, S> &m)
+{
+ SquareMatrix<T, S> r = m;
+ return r.invert();
+}
+
} // namespace LinAl
} // namespace Msp