X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Flinal%2Fmatrix.h;h=929c48247e517aa47d837df1438c94465e25064a;hb=fb9e6b5ff48e10ea2217cf539e0461956abf02cf;hp=94a6e0991b2d13502e2f998107d5e26f5831ad04;hpb=a3d9772a9fd483278b6248a811dc6f4ce968892b;p=libs%2Fmath.git

diff --git a/source/linal/matrix.h b/source/linal/matrix.h
index 94a6e09..929c482 100644
--- a/source/linal/matrix.h
+++ b/source/linal/matrix.h
@@ -8,7 +8,7 @@ namespace Msp {
 namespace LinAl {
 
 /**
-A general mathematical matrix.
+A general mathematical matrix with M rows and N columns.
 */
 template<typename T, unsigned M, unsigned N>
 class Matrix
@@ -25,10 +25,13 @@ public:
 	static Matrix from_columns(const Vector<T, M> *);
 	static Matrix from_rows(const Vector<T, N> *);
 
-	T &element(unsigned, unsigned);
-	const T &element(unsigned, unsigned) const;
-	T &operator()(unsigned, unsigned);
-	const T &operator()(unsigned, unsigned) const;
+	T &element(unsigned i, unsigned j) { return data[i+M*j]; }
+	const T &element(unsigned i, unsigned j) const { return data[i+M*j]; }
+	T &operator()(unsigned i, unsigned j) { return element(i, j); }
+	const T &operator()(unsigned i, unsigned j) const { return element(i, j); }
+
+	template<unsigned P, unsigned Q>
+	Matrix<T, P, Q> block(unsigned, unsigned) const;
 
 	Matrix &operator*=(T);
 	Matrix &operator/=(T);
@@ -54,9 +57,11 @@ inline Matrix<T, M, N>::Matrix(const T *d)
 
 template<typename T, unsigned M, unsigned N>
 template<typename U>
-inline Matrix<T, M, N>::Matrix(const Matrix<U, M, N> &m)
+inline Matrix<T, M, N>::Matrix(const Matrix<U, M, N> &other)
 {
-	std::copy(m.data, m.data+M*N, data);
+	for(unsigned i=0; i<M; ++i)
+		for(unsigned j=0; j<N; ++j)
+			element(i, j) = other(i, j);
 }
 
 template<typename T, unsigned M, unsigned N>
@@ -66,6 +71,7 @@ inline Matrix<T, M, N> Matrix<T, M, N>::from_columns(const Vector<T, M> *v)
 	for(unsigned i=0; i<M; ++i)
 		for(unsigned j=0; j<N; ++j)
 			m(i, j) = v[j][i];
+	return m;
 }
 
 template<typename T, unsigned M, unsigned N>
@@ -75,30 +81,18 @@ inline Matrix<T, M, N> Matrix<T, M, N>::from_rows(const Vector<T, N> *v)
 	for(unsigned i=0; i<M; ++i)
 		for(unsigned j=0; j<N; ++j)
 			m(i, j) = v[i][j];
+	return m;
 }
 
 template<typename T, unsigned M, unsigned N>
-inline T &Matrix<T, M, N>::element(unsigned i, unsigned j)
-{
-	return data[i+M*j];
-}
-
-template<typename T, unsigned M, unsigned N>
-inline const T &Matrix<T, M, N>::element(unsigned i, unsigned j) const
-{
-	return data[i+M*j];
-}
-
-template<typename T, unsigned M, unsigned N>
-inline T &Matrix<T, M, N>::operator()(unsigned i, unsigned j)
-{
-	return element(i, j);
-}
-
-template<typename T, unsigned M, unsigned N>
-inline const T &Matrix<T, M, N>::operator()(unsigned i, unsigned j) const
+template<unsigned P, unsigned Q>
+inline Matrix<T, P, Q> Matrix<T, M, N>::block(unsigned y, unsigned x) const
 {
-	return element(i, j);
+	Matrix<T, P, Q> r;
+	for(unsigned j=0; j<P; ++j)
+		for(unsigned i=0; i<Q; ++i)
+			r(j, i) = element(y+j, x+i);
+	return r;
 }
 
 template<typename T, unsigned M, unsigned N>
@@ -211,8 +205,9 @@ inline bool operator==(const Matrix<T, M, N> &a, const Matrix<T, M, N> &b)
 template<typename T, unsigned M, unsigned N>
 inline Matrix<T, M, N> &Matrix<T, M, N>::exchange_rows(unsigned i, unsigned j)
 {
+	using std::swap;
 	for(unsigned k=0; k<N; ++k)
-		std::swap(element(i, k), element(j, k));
+		swap(element(i, k), element(j, k));
 	return *this;
 }