Math function usage fixes

[libs/math.git] / source / linal / squarematrix.h

diff --git a/source/linal/squarematrix.h b/source/linal/squarematrix.h
index ee86e13921219702fa58a682c4b5ab2bb5cfb290..1cdc56726455f9ab2b97589b1b93bacbad702eac 100644 (file)
--- a/source/linal/squarematrix.h
+++ b/source/linal/squarematrix.h
@@ -1,6 +1,7 @@
 #ifndef MSP_LINAL_SQUAREMATRIX_H_
 #define MSP_LINAL_SQUAREMATRIX_H_
 
+#include <cmath>
 #include <stdexcept>
 #include "matrix.h"
 
@@ -14,6 +15,10 @@ public:
        virtual ~not_invertible() throw() { }
 };
 
+/**
+A mathematical matrix with S rows and columns.  Some operations are provided
+here that are only possible for square matrices.
+*/
 template<typename T, unsigned S>
 class SquareMatrix: public Matrix<T, S, S>
 {
@@ -48,6 +53,8 @@ SquareMatrix<T, S> &SquareMatrix<T, S>::operator*=(const SquareMatrix<T, S> &m)
 template<typename T, unsigned S>
 SquareMatrix<T, S> &SquareMatrix<T, S>::invert()
 {
+       using std::abs;
+
        SquareMatrix<T, S> r = identity();
        for(unsigned i=0; i<S; ++i)
        {