0000856: Wrong inverse of a matrix

src/Base/Matrix.h

@@ -134,9 +134,11 @@ public:
   /// transform (move,scale,rotate) around a point
   void transform    (const Vector3f& rclVct, const Matrix4D& rclMtrx);
   void transform    (const Vector3d& rclVct, const Matrix4D& rclMtrx);
+  /// Matrix is expected to have a 3x3 rotation matrix.
   void inverse      (void);
-  /// if matrix is orthogonal a special way of getting the inverse is used
+  /// Matrix is expected to have a 3x3 rotation matrix.
   void inverseOrthogonal(void);
+  /// Arbitrary, non-singular matrix
   void inverseGauss (void);
   void transpose    (void);
   //@}

src/Base/MatrixPyImp.cpp

@@ -342,7 +342,7 @@ PyObject* MatrixPy::invert(PyObject * args)
 
     PY_TRY {
         if (getMatrixPtr()->determinant() > DBL_EPSILON)
-            getMatrixPtr()->inverse();
+            getMatrixPtr()->inverseGauss();
         else {
             PyErr_SetString(PyExc_Exception, "Cannot invert singular matrix");
             return 0;
@@ -361,7 +361,7 @@ PyObject* MatrixPy::inverse(PyObject * args)
     PY_TRY {
         if (getMatrixPtr()->determinant() > DBL_EPSILON) {
             Base::Matrix4D m = *getMatrixPtr();
-            m.inverse();
+            m.inverseGauss();
             return new MatrixPy(m);
         }
         else {

src/Mod/Test/BaseTests.py

@@ -149,6 +149,11 @@ class ParameterTestCase(unittest.TestCase):
         self.TestPar.RemString("44")
         self.failUnless(self.TestPar.GetString("44","hallo") == "hallo","Deletion error at String")
 
+    def testMatrix(self):
+        m=FreeCAD.Matrix(4,2,1,0,1,1,1,0,0,0,1,0,0,0,0,1)
+        u=m.multiply(m.inverse())
+        self.failUnless(u==FreeCAD.Matrix(),"Invalid inverse of matrix")
+
     def testNesting(self):
         # Parameter testing
         #FreeCAD.Console.PrintLog("Base::ParameterTestCase::testNesting\n")