ENH: Add check if optimizer supports scales

Not all optimizers support scale weights.  The
itkImageRegistrationMethodv4 was unconditionally
setting the scales and causing a confusing warning
message to be presented (identified in python, but
also present in c++).  Providing an overridable member
function that returns the support for weighting scales
allow suppression of the warnings.

Modules/Numerics/Optimizers/include/itkLBFGSBOptimizer.h

@@ -194,6 +194,13 @@ class ITKOptimizers_EXPORT LBFGSBOptimizer : public SingleValuedNonLinearVnlOpti
   const std::string
   GetStopConditionDescription() const override;
 
+  /** Returns false unconditionally because LBFGSBOptimizer does not support using scales. */
+  bool
+  CanUseScales() const override
+  {
+    return false;
+  }
+
 protected:
   LBFGSBOptimizer();
   ~LBFGSBOptimizer() override;

Modules/Numerics/Optimizers/include/itkSingleValuedNonLinearVnlOptimizer.h

@@ -101,6 +101,15 @@ class ITKOptimizers_EXPORT SingleValuedNonLinearVnlOptimizer : public SingleValu
   itkGetConstReferenceMacro(CachedDerivative, DerivativeType);
   itkGetConstReferenceMacro(CachedCurrentPosition, ParametersType);
 
+  /** Returns true if derived optimizer supports using scales.
+   * For optimizers that do not support scaling, this
+   * default function is overriden to return false.*/
+  virtual bool
+  CanUseScales() const
+  {
+    return true;
+  }
+
 protected:
   SingleValuedNonLinearVnlOptimizer();
   ~SingleValuedNonLinearVnlOptimizer() override;

Modules/Numerics/Optimizersv4/include/itkLBFGSBOptimizerv4.h

@@ -170,6 +170,13 @@ class ITKOptimizersv4_EXPORT LBFGSBOptimizerv4 : public LBFGSOptimizerBasev4<vnl
    * function. */
   itkGetConstReferenceMacro(InfinityNormOfProjectedGradient, double);
 
+  /** Returns false unconditionally because LBFGSBOptimizerv4 does not support using scales. */
+  bool
+  CanUseScales() const override
+  {
+    return false;
+  }
+
 protected:
   LBFGSBOptimizerv4();
   ~LBFGSBOptimizerv4() override;

Modules/Numerics/Optimizersv4/include/itkObjectToObjectOptimizerBase.h

@@ -262,6 +262,15 @@ class ITK_TEMPLATE_EXPORT ObjectToObjectOptimizerBaseTemplate : public Object
   virtual const StopConditionReturnStringType
   GetStopConditionDescription() const = 0;
 
+  /** Returns true if derived optimizer supports using scales.
+   * For optimizers that do not support scaling, this
+   * default function is overriden to return false.*/
+  virtual bool
+  CanUseScales() const
+  {
+    return true;
+  }
+
 protected:
   /** Default constructor */
   ObjectToObjectOptimizerBaseTemplate();

Modules/Registration/RegistrationMethodsv4/include/itkImageRegistrationMethodv4.hxx

@@ -737,7 +737,8 @@ ImageRegistrationMethodv4<TFixedImage, TMovingImage, TTransform, TVirtualImage,
 
   this->m_Optimizer->SetMetric(this->m_Metric);
 
-  if ((this->m_Optimizer->GetScales()).Size() != this->m_OutputTransform->GetNumberOfLocalParameters())
+  if (this->m_Optimizer->CanUseScales() &&
+      ((this->m_Optimizer->GetScales()).Size() != this->m_OutputTransform->GetNumberOfLocalParameters()))
   {
     using ScalesType = typename OptimizerType::ScalesType;
     ScalesType scales;