* update test to expose bug #57
* update createRandomMatrixOfRank to support fixed size

Eigen/src/QR/ColPivotingHouseholderQR.h

diff --git a/Eigen/src/QR/ColPivotingHouseholderQR.h b/Eigen/src/QR/ColPivotingHouseholderQR.h
index c4c7d2d..0898b5d 100644
--- a/Eigen/src/QR/ColPivotingHouseholderQR.h
+++ b/Eigen/src/QR/ColPivotingHouseholderQR.h
@@ -351,7 +351,6 @@
   }
 
   const int rows = m_qr.rows();
-  const int cols = b.cols();
   ei_assert(b.rows() == rows);
 
   typename OtherDerived::PlainMatrixType c(b);

test/main.h

diff --git a/test/main.h b/test/main.h
index 8c93e85..51b7198 100644
--- a/test/main.h
+++ b/test/main.h
@@ -248,18 +248,22 @@
 void createRandomMatrixOfRank(int desired_rank, int rows, int cols, MatrixType& m)
 {
   typedef typename ei_traits<MatrixType>::Scalar Scalar;
-  typedef Matrix<Scalar, Dynamic, 1> VectorType;
+  enum { Rows = MatrixType::RowsAtCompileTime, Cols = MatrixType::ColsAtCompileTime };
 
-  MatrixType a = MatrixType::Random(rows,rows);
+  typedef Matrix<Scalar, Dynamic, 1> VectorType;
+  typedef Matrix<Scalar, Rows, Rows> MatrixAType;
+  typedef Matrix<Scalar, Cols, Cols> MatrixBType;
+
+  MatrixAType a = MatrixAType::Random(rows,rows);
   MatrixType d = MatrixType::Identity(rows,cols);
-  MatrixType  b = MatrixType::Random(cols,cols);
+  MatrixBType  b = MatrixBType::Random(cols,cols);
 
   // set the diagonal such that only desired_rank non-zero entries reamain
   const int diag_size = std::min(d.rows(),d.cols());
   d.diagonal().segment(desired_rank, diag_size-desired_rank) = VectorType::Zero(diag_size-desired_rank);
 
-  HouseholderQR<MatrixType> qra(a);
-  HouseholderQR<MatrixType> qrb(b);
+  HouseholderQR<MatrixAType> qra(a);
+  HouseholderQR<MatrixBType> qrb(b);
   m = qra.matrixQ() * d * qrb.matrixQ();
 }
 

test/qr_colpivoting.cpp

diff --git a/test/qr_colpivoting.cpp b/test/qr_colpivoting.cpp
index 588a41e..e0edad8 100644
--- a/test/qr_colpivoting.cpp
+++ b/test/qr_colpivoting.cpp
@@ -63,6 +63,40 @@
   VERIFY(!qr.solve(m3, &m2));
 }
 
+template<typename MatrixType, int Cols2> void qr_fixedsize()
+{
+  enum { Rows = MatrixType::RowsAtCompileTime, Cols = MatrixType::ColsAtCompileTime };
+  typedef typename MatrixType::Scalar Scalar;
+  int rank = ei_random<int>(1, std::min(int(Rows), int(Cols))-1);
+  Matrix<Scalar,Rows,Cols> m1;
+  createRandomMatrixOfRank(rank,Rows,Cols,m1);
+  ColPivotingHouseholderQR<Matrix<Scalar,Rows,Cols> > qr(m1);
+  VERIFY_IS_APPROX(rank, qr.rank());
+  VERIFY(Cols - qr.rank() == qr.dimensionOfKernel());
+  VERIFY(!qr.isInjective());
+  VERIFY(!qr.isInvertible());
+  VERIFY(!qr.isSurjective());
+
+  Matrix<Scalar,Rows,Cols> r = qr.matrixQR();
+  // FIXME need better way to construct trapezoid
+  for(int i = 0; i < Rows; i++) for(int j = 0; j < Cols; j++) if(i>j) r(i,j) = Scalar(0);
+
+  Matrix<Scalar,Rows,Cols> b = qr.matrixQ() * r;
+
+  Matrix<Scalar,Rows,Cols> c = MatrixType::Zero(Rows,Cols);
+
+  for(int i = 0; i < Cols; ++i) c.col(qr.colsPermutation().coeff(i)) = b.col(i);
+  VERIFY_IS_APPROX(m1, c);
+
+  Matrix<Scalar,Cols,Cols2> m2 = Matrix<Scalar,Cols,Cols2>::Random(Cols,Cols2);
+  Matrix<Scalar,Rows,Cols2> m3 = m1*m2;
+  m2 = Matrix<Scalar,Cols,Cols2>::Random(Cols,Cols2);
+  VERIFY(qr.solve(m3, &m2));
+  VERIFY_IS_APPROX(m3, m1*m2);
+  m3 = Matrix<Scalar,Rows,Cols2>::Random(Rows,Cols2);
+  VERIFY(!qr.solve(m3, &m2));
+}
+
 template<typename MatrixType> void qr_invertible()
 {
   typedef typename NumTraits<typename MatrixType::Scalar>::Real RealScalar;
@@ -121,6 +155,9 @@
     CALL_SUBTEST( qr<MatrixXd>() );
     CALL_SUBTEST( qr<MatrixXcd>() );
   }
+  
+  CALL_SUBTEST(( qr_fixedsize<Matrix<float,3,5>, 4 >() ));
+  CALL_SUBTEST(( qr_fixedsize<Matrix<double,6,2>, 3 >() ));
 
   for(int i = 0; i < g_repeat; i++) {
     CALL_SUBTEST( qr_invertible<MatrixXf>() );