BUG: Fix setting zero sized CompositeTransforms

Author: blowekamp

Modules/Core/Transform/include/itkCompositeTransform.hxx

@@ -647,6 +647,11 @@ CompositeTransform<TParametersValueType, VDimension>::SetParameters(const Parame
                                                                          << this->GetNumberOfParameters() << '.');
   }
 
+  if (transforms.size() == 0)
+  {
+    return; // Nothing to do, no transforms.
+  }
+
   if (transforms.size() == 1)
   {
     /* Avoid unnecessary copying. See comments below */

Modules/Core/Transform/test/itkCompositeTransformTest.cxx

@@ -130,6 +130,11 @@ itkCompositeTransformTest(int, char *[])
   ITK_TEST_EXPECT_EQUAL(compositeTransform->GetParameters().Size(), 0u);
   ITK_TEST_EXPECT_EQUAL(compositeTransform->GetFixedParameters().Size(), 0u);
 
+  /* Test that we can set with a zero length array */
+  CompositeType::ParametersType parameters(0);
+  compositeTransform->SetParameters(parameters);
+  compositeTransform->SetFixedParameters(parameters);
+
   {
     CompositeType::InputPointType inputPoint;
     inputPoint[0] = 1.1;