X-Git-Url: http://git.tdb.fi/?p=libs%2Fmath.git;a=blobdiff_plain;f=source%2Flinal%2Fsquarematrix.h;h=4cdc9e88f7288654d4dcbae9d2ec006517bfb734;hp=6cda86a5baa6b202ec00dba93acb0a152b03a985;hb=a3d9772a9fd483278b6248a811dc6f4ce968892b;hpb=79b2de777a3841bced5fd782a46166fc4d9d7489

diff --git a/source/linal/squarematrix.h b/source/linal/squarematrix.h
index 6cda86a..4cdc9e8 100644
--- a/source/linal/squarematrix.h
+++ b/source/linal/squarematrix.h
@@ -1,26 +1,108 @@
 #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() { }
 	SquareMatrix(const T *);
 	template<typename U>
 	SquareMatrix(const Matrix<U, S, S> &);
+
 	static SquareMatrix identity();
 
 	SquareMatrix &operator*=(const SquareMatrix &);
 
-	void invert();
+	SquareMatrix &invert();
 };
 
+template<typename T, unsigned S>
+SquareMatrix<T, S>::SquareMatrix(const T *d):
+	Matrix<T, S, S>(d)
+{ }
+
+template<typename T, unsigned S>
+template<typename U>
+SquareMatrix<T, S>::SquareMatrix(const Matrix<U, S, S> &m):
+	Matrix<T, S, S>(m)
+{ }
+
+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