Further LU test improvements. I'm not aware of any test failures anymore, not even with huge numbers of repetitions.

Finally the createRandomMatrixOfRank() function is renamed to createRandomPIMatrixOfRank, where PI stands for 'partial isometry', that is, a matrix whose singular values are 0 or 1.

test/inverse.cpp

@@ -42,7 +42,7 @@ template<typename MatrixType> void inverse(const MatrixType& m)
              m2(rows, cols),
              mzero = MatrixType::Zero(rows, cols),
              identity = MatrixType::Identity(rows, rows);
-  createRandomProjectionOfRank(rows,rows,rows,m1);
+  createRandomPIMatrixOfRank(rows,rows,rows,m1);
   m2 = m1.inverse();
   VERIFY_IS_APPROX(m1, m2.inverse() );