more changes in ScalarMultiple, reintroduce FloatingPoint in NumTraits, improve

examples

doc/examples/class_Block.cpp

@@ -7,17 +7,20 @@ Eigen::Block<Derived, 2, 2>
 topLeft2x2Corner(MatrixBase<Scalar, Derived>& m)
 {
   return Eigen::Block<Derived, 2, 2>(m.ref(), 0, 0);
-  // note: tempting as it is, writing "m.block<2,2>(0,0)" here
-  // causes a compile error with g++ 4.2, apparently due to
-  // g++ getting confused by the many template types and
-  // template arguments involved.
+}
+
+template<typename Scalar, typename Derived>
+const Eigen::Block<Derived, 2, 2>
+topLeft2x2Corner(const MatrixBase<Scalar, Derived>& m)
+{
+  return Eigen::Block<Derived, 2, 2>(m.ref(), 0, 0);
 }
 
 int main(int, char**)
 {
   Matrix3d m = Matrix3d::identity();
-  cout << topLeft2x2Corner(m) << endl;
-  topLeft2x2Corner(m) *= 2;
+  cout << topLeft2x2Corner(4*m) << endl; // calls the const version
+  topLeft2x2Corner(m) *= 2;              // calls the non-const version
   cout << "Now the matrix m is:" << endl << m << endl;
   return 0;
 }

doc/examples/class_Cast.cpp

@@ -3,14 +3,16 @@ USING_PART_OF_NAMESPACE_EIGEN
 using namespace std;
 
 template<typename Scalar, typename Derived>
-Eigen::Cast<double, Derived>
-castToDouble(const MatrixBase<Scalar, Derived>& m)
+const Eigen::Cast<
+  typename Eigen::NumTraits<Scalar>::FloatingPoint,
+  Derived
+>
+castToFloatingPoint(const MatrixBase<Scalar, Derived>& m)
 {
-  return Eigen::Cast<double, Derived>(m.ref());
-  // note: tempting as it is, writing "m.cast<double>()" here
-  // causes a compile error with g++ 4.2, apparently due to
-  // g++ getting confused by the many template types and
-  // template arguments involved.
+  return Eigen::Cast<
+    typename Eigen::NumTraits<Scalar>::FloatingPoint,
+    Derived
+  >(m.ref());
 }
 
 int main(int, char**)
@@ -18,6 +20,6 @@ int main(int, char**)
   Matrix2i m = Matrix2i::random();
   cout << "Here's the matrix m. It has coefficients of type int."
        << endl << m << endl;
-  cout << "Here's 0.05*m:" << endl << 0.05 * castToDouble(m) << endl;
+  cout << "Here's m/20:" << endl << castToFloatingPoint(m)/20 << endl;
   return 0;
 }

doc/examples/class_Column.cpp

@@ -6,14 +6,21 @@ template<typename Scalar, typename Derived>
 Eigen::Column<Derived>
 firstColumn(MatrixBase<Scalar, Derived>& m)
 {
-  return m.col(0);
+  return Eigen::Column<Derived>(m.ref(), 0);
+}
+
+template<typename Scalar, typename Derived>
+const Eigen::Column<Derived>
+firstColumn(const MatrixBase<Scalar, Derived>& m)
+{
+  return Eigen::Column<Derived>(m.ref(), 0);
 }
 
 int main(int, char**)
 {
   Matrix4d m = Matrix4d::identity();
-  cout << firstColumn(m) << endl;
-  firstColumn(m) *= 5;
+  cout << firstColumn(2*m) << endl; // calls the const version
+  firstColumn(m) *= 5;              // calls the non-const version
   cout << "Now the matrix m is:" << endl << m << endl;
   return 0;
 }

doc/examples/class_DynBlock.cpp

@@ -6,14 +6,21 @@ template<typename Scalar, typename Derived>
 Eigen::DynBlock<Derived>
 topLeftCorner(MatrixBase<Scalar, Derived>& m, int rows, int cols)
 {
-  return m.dynBlock(0, 0, rows, cols);
+  return Eigen::DynBlock<Derived>(m.ref(), 0, 0, rows, cols);
+}
+
+template<typename Scalar, typename Derived>
+const Eigen::DynBlock<Derived>
+topLeftCorner(const MatrixBase<Scalar, Derived>& m, int rows, int cols)
+{
+  return Eigen::DynBlock<Derived>(m.ref(), 0, 0, rows, cols);
 }
 
 int main(int, char**)
 {
   Matrix4d m = Matrix4d::identity();
-  cout << topLeftCorner(m, 2, 3) << endl;
-  topLeftCorner(m, 2, 3) *= 5;
+  cout << topLeftCorner(4*m, 2, 3) << endl; // calls the const version
+  topLeftCorner(m, 2, 3) *= 5;              // calls the non-const version
   cout << "Now the matrix m is:" << endl << m << endl;
   return 0;
 }

doc/examples/class_Row.cpp

@@ -6,14 +6,21 @@ template<typename Scalar, typename Derived>
 Eigen::Row<Derived>
 firstRow(MatrixBase<Scalar, Derived>& m)
 {
-  return m.row(0);
+  return Eigen::Row<Derived>(m.ref(), 0);
+}
+
+template<typename Scalar, typename Derived>
+const Eigen::Row<Derived>
+firstRow(const MatrixBase<Scalar, Derived>& m)
+{
+  return Eigen::Row<Derived>(m.ref(), 0);
 }
 
 int main(int, char**)
 {
   Matrix4d m = Matrix4d::identity();
-  cout << firstRow(m) << endl;
-  firstRow(m) *= 5;
+  cout << firstRow(2*m) << endl; // calls the const version
+  firstRow(m) *= 5;              // calls the non-const version
   cout << "Now the matrix m is:" << endl << m << endl;
   return 0;
 }