Added scalar * operator to VectorValues

gtsam/linear/VectorValues.cpp

@@ -246,6 +246,21 @@ namespace gtsam {
     return *this - c;
   }
 
+  /* ************************************************************************* */
+  VectorValues operator*(const double a, const VectorValues &v)
+  {
+    VectorValues result;
+    BOOST_FOREACH(const VectorValues::KeyValuePair& v, v)
+      result.values_.insert(result.values_.end(), make_pair(v.first, a * v.second));
+    return result;
+  }
+
+  /* ************************************************************************* */
+  VectorValues VectorValues::scale(const double a) const
+  {
+    return a * *this;
+  }
+
   /* ************************************************************************* */
   VectorValues& VectorValues::operator*=(double alpha)
   {

gtsam/linear/VectorValues.h

@@ -272,6 +272,12 @@ namespace gtsam {
      *  structure (checked when NDEBUG is not defined). */
     VectorValues subtract(const VectorValues& c) const;
 
+    /** Element-wise scaling by a constant. */
+    friend VectorValues operator*(const double a, const VectorValues &v);
+
+    /** Element-wise scaling by a constant. */
+    VectorValues scale(const double a) const;
+
     /** Element-wise scaling by a constant in-place. */
     VectorValues& operator*=(double alpha);
 

gtsam/linear/tests/testVectorValuesUnordered.cpp

@@ -154,6 +154,8 @@ TEST(VectorValues, LinearAlgebra)
   VectorValues scalActual = test1;
   scalActual *= 5.0;
   EXPECT(assert_equal(scalExpected, scalActual.vector()));
+  VectorValues scal2Actual = 5.0 * test1;
+  EXPECT(assert_equal(scalExpected, scal2Actual.vector()));
 }
 
 /* ************************************************************************* */