[Extend] Implement extractOldVelocity()

src/timestepping.hh

@@ -14,6 +14,7 @@ class TimeSteppingScheme {
   void virtual postProcess(Vector const &iterate) = 0;
   void virtual extractDisplacement(Vector &displacement) const = 0;
   void virtual extractVelocity(Vector &velocity) const = 0;
+  void virtual extractOldVelocity(Vector &velocity) const = 0;
 };
 
 #include "timestepping/newmark.hh"

src/timestepping/backward_euler.cc

@@ -108,3 +108,9 @@ void BackwardEuler<Vector, Matrix, Function, dim>::extractVelocity(
 
   velocity = v;
 }
+
+template <class Vector, class MatrixType, class FunctionType, size_t dim>
+void BackwardEuler<Vector, MatrixType, FunctionType, dim>::extractOldVelocity(
+    Vector &velocity) const {
+  velocity = v_o;
+}

src/timestepping/backward_euler.hh

@@ -15,6 +15,7 @@ class BackwardEuler : public TimeSteppingScheme<Vector, Matrix, Function, dim> {
   void postProcess(Vector const &) override;
   void extractDisplacement(Vector &) const override;
   void extractVelocity(Vector &) const override;
+  void extractOldVelocity(Vector &) const override;
 
 private:
   Matrix const &A;

src/timestepping/newmark.cc

@@ -123,3 +123,9 @@ void Newmark<Vector, Matrix, Function, dim>::extractVelocity(Vector &velocity)
 
   velocity = v;
 }
+
+template <class Vector, class MatrixType, class FunctionType, size_t dim>
+void Newmark<Vector, MatrixType, FunctionType, dim>::extractOldVelocity(
+    Vector &velocity) const {
+  velocity = v_o;
+}

src/timestepping/newmark.hh

@@ -16,6 +16,7 @@ class Newmark : public TimeSteppingScheme<Vector, Matrix, Function, dim> {
   void postProcess(Vector const &) override;
   void extractDisplacement(Vector &) const override;
   void extractVelocity(Vector &) const override;
+  void extractOldVelocity(Vector &) const override;
 
 private:
   Matrix const &A;