From 2f60979bbbd6458bd446c0435ea14f043f90374c Mon Sep 17 00:00:00 2001
From: Bradley Lowekamp <blowekamp@mail.nih.gov>
Date: Thu, 28 Oct 2021 10:40:23 -0400
Subject: [PATCH] ENH: Remove LBFGS2's pimpl member

The lbfgs library is not part of the public interface for the
Optimizerv4 library since the LBFGS2 optimizer is no longer compiled
into the library. Since the lbfgs methods and structures are used in
the hxx files, there is not purpase to keep the structures and usage
encapsulated in a private implementation.
---
 .../include/itkLBFGS2Optimizerv4.h            |   4 +-
 .../include/itkLBFGS2Optimizerv4.hxx          | 109 ++++++++----------
 .../Optimizersv4/src/itkLBFGS2Optimizerv4.cxx |   2 +
 3 files changed, 55 insertions(+), 60 deletions(-)

diff --git a/Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.h b/Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.h
index 53afacf01ab..640807b80bc 100644
--- a/Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.h
+++ b/Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.h
@@ -22,6 +22,8 @@
 #include "ITKOptimizersv4Export.h"
 #include <memory>
 
+#include "lbfgs.h"
+
 namespace itk
 {
 /*** \class LBFGS2Optimizerv4Enums
@@ -504,7 +506,7 @@ class ITK_TEMPLATE_EXPORT LBFGS2Optimizerv4Template
 private:
   // Private Implementation (Pimpl), to hide liblbfgs data structures
   class PrivateImplementationHolder;
-  std::unique_ptr<PrivateImplementationHolder> m_Pimpl;
+  lbfgs_parameter_t m_Parameters;
 
   bool   m_EstimateScalesAtEachIteration;
   double m_CurrentStepSize;
diff --git a/Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.hxx b/Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.hxx
index 051faf5dc56..989ead2573e 100644
--- a/Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.hxx
+++ b/Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.hxx
@@ -22,25 +22,16 @@
 #include "itkMacro.h"
 #include "itkMath.h"
 
-#include "lbfgs.h"
 
 namespace itk
 {
 
-template <typename TInternalComputationValueType>
-class LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrivateImplementationHolder
-{
-public:
-  lbfgs_parameter_t m_Parameters;
-};
-
 
 template <typename TInternalComputationValueType>
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::LBFGS2Optimizerv4Template()
-  : m_Pimpl(new PrivateImplementationHolder)
 {
   // Initialize to default parameters
-  lbfgs_parameter_init(&m_Pimpl->m_Parameters);
+  lbfgs_parameter_init(&m_Parameters);
   m_StatusCode = 100;
 
   this->m_EstimateScalesAtEachIteration = true;
@@ -55,22 +46,22 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrintSelf(std::ostream & os, Indent indent) const
 {
   Superclass::PrintSelf(os, indent);
-  os << indent << "m: " << m_Pimpl->m_Parameters.m << std::endl;
-  os << indent << "epsilon: " << m_Pimpl->m_Parameters.epsilon << std::endl;
-  os << indent << "past: " << m_Pimpl->m_Parameters.past << std::endl;
-  os << indent << "delta: " << m_Pimpl->m_Parameters.delta << std::endl;
-  os << indent << "max_iterations: " << m_Pimpl->m_Parameters.max_iterations << std::endl;
-  os << indent << "linesearch: " << m_Pimpl->m_Parameters.linesearch << std::endl;
-  os << indent << "max_linesearch: " << m_Pimpl->m_Parameters.max_linesearch << std::endl;
-  os << indent << "min_step: " << m_Pimpl->m_Parameters.min_step << std::endl;
-  os << indent << "max_step: " << m_Pimpl->m_Parameters.max_step << std::endl;
-  os << indent << "ftol: " << m_Pimpl->m_Parameters.ftol << std::endl;
-  os << indent << "wolfe: " << m_Pimpl->m_Parameters.wolfe << std::endl;
-  os << indent << "gtol: " << m_Pimpl->m_Parameters.gtol << std::endl;
-  os << indent << "xtol: " << m_Pimpl->m_Parameters.xtol << std::endl;
-  os << indent << "orthantwise_c: " << m_Pimpl->m_Parameters.orthantwise_c << std::endl;
-  os << indent << "orthantwise_start: " << m_Pimpl->m_Parameters.orthantwise_start << std::endl;
-  os << indent << "orthantwise_end: " << m_Pimpl->m_Parameters.orthantwise_end << std::endl;
+  os << indent << "m: " << m_Parameters.m << std::endl;
+  os << indent << "epsilon: " << m_Parameters.epsilon << std::endl;
+  os << indent << "past: " << m_Parameters.past << std::endl;
+  os << indent << "delta: " << m_Parameters.delta << std::endl;
+  os << indent << "max_iterations: " << m_Parameters.max_iterations << std::endl;
+  os << indent << "linesearch: " << m_Parameters.linesearch << std::endl;
+  os << indent << "max_linesearch: " << m_Parameters.max_linesearch << std::endl;
+  os << indent << "min_step: " << m_Parameters.min_step << std::endl;
+  os << indent << "max_step: " << m_Parameters.max_step << std::endl;
+  os << indent << "ftol: " << m_Parameters.ftol << std::endl;
+  os << indent << "wolfe: " << m_Parameters.wolfe << std::endl;
+  os << indent << "gtol: " << m_Parameters.gtol << std::endl;
+  os << indent << "xtol: " << m_Parameters.xtol << std::endl;
+  os << indent << "orthantwise_c: " << m_Parameters.orthantwise_c << std::endl;
+  os << indent << "orthantwise_start: " << m_Parameters.orthantwise_start << std::endl;
+  os << indent << "orthantwise_end: " << m_Parameters.orthantwise_end << std::endl;
 }
 
 
@@ -114,7 +105,7 @@ LBFGS2Optimizerv4Template<TInternalComputationValueType>::ResumeOptimization()
                        LBFGS2Optimizerv4Template::EvaluateCostCallback,
                        LBFGS2Optimizerv4Template::UpdateProgressCallback,
                        this,
-                       &m_Pimpl->m_Parameters);
+                       &m_Parameters);
 
   // Match the behavior of other optimizer setting the current
   // iteration to the max when iteration limit is reached
@@ -309,7 +300,7 @@ template <typename TInternalComputationValueType>
 void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetHessianApproximationAccuracy(int m)
 {
-  m_Pimpl->m_Parameters.m = m;
+  m_Parameters.m = m;
   this->Modified();
 }
 
@@ -317,7 +308,7 @@ template <typename TInternalComputationValueType>
 int
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetHessianApproximationAccuracy() const
 {
-  return m_Pimpl->m_Parameters.m;
+  return m_Parameters.m;
 }
 
 template <typename TInternalComputationValueType>
@@ -325,7 +316,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetSolutionAccuracy(
   LBFGS2Optimizerv4Template::PrecisionType epsilon)
 {
-  m_Pimpl->m_Parameters.epsilon = epsilon;
+  m_Parameters.epsilon = epsilon;
   this->Modified();
 }
 
@@ -333,14 +324,14 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetSolutionAccuracy() const
 {
-  return m_Pimpl->m_Parameters.epsilon;
+  return m_Parameters.epsilon;
 }
 
 template <typename TInternalComputationValueType>
 void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetDeltaConvergenceDistance(int nPast)
 {
-  m_Pimpl->m_Parameters.past = nPast;
+  m_Parameters.past = nPast;
   this->Modified();
 }
 
@@ -348,7 +339,7 @@ template <typename TInternalComputationValueType>
 int
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetDeltaConvergenceDistance() const
 {
-  return m_Pimpl->m_Parameters.past;
+  return m_Parameters.past;
 }
 
 template <typename TInternalComputationValueType>
@@ -356,7 +347,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetDeltaConvergenceTolerance(
   LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType tol)
 {
-  m_Pimpl->m_Parameters.delta = tol;
+  m_Parameters.delta = tol;
   this->Modified();
 }
 
@@ -364,14 +355,14 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetDeltaConvergenceTolerance() const
 {
-  return m_Pimpl->m_Parameters.delta;
+  return m_Parameters.delta;
 }
 
 template <typename TInternalComputationValueType>
 void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetMaximumIterations(int maxIterations)
 {
-  m_Pimpl->m_Parameters.max_iterations = maxIterations;
+  m_Parameters.max_iterations = maxIterations;
   this->Modified();
 }
 
@@ -380,7 +371,7 @@ template <typename TInternalComputationValueType>
 int
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetMaximumIterations() const
 {
-  return m_Pimpl->m_Parameters.max_iterations;
+  return m_Parameters.max_iterations;
 }
 
 // translate to lbfgs.h enum
@@ -415,7 +406,7 @@ LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetLineSearch(
     lbfgsLineSearch = LBFGS_LINESEARCH_MORETHUENTE;
   }
 
-  m_Pimpl->m_Parameters.linesearch = lbfgsLineSearch;
+  m_Parameters.linesearch = lbfgsLineSearch;
   this->Modified();
 }
 
@@ -424,7 +415,7 @@ typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::LineSearchMet
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetLineSearch() const
 {
   LineSearchMethodEnum linesearch = LineSearchMethodEnum::LINESEARCH_DEFAULT;
-  int                  lbfgsLineSearch = m_Pimpl->m_Parameters.linesearch;
+  int                  lbfgsLineSearch = m_Parameters.linesearch;
   if (lbfgsLineSearch == LBFGS_LINESEARCH_BACKTRACKING)
   {
     linesearch = LineSearchMethodEnum::LINESEARCH_BACKTRACKING;
@@ -453,7 +444,7 @@ template <typename TInternalComputationValueType>
 void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetMaximumLineSearchEvaluations(int n)
 {
-  m_Pimpl->m_Parameters.max_linesearch = n;
+  m_Parameters.max_linesearch = n;
   this->Modified();
 }
 
@@ -461,7 +452,7 @@ template <typename TInternalComputationValueType>
 int
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetMaximumLineSearchEvaluations() const
 {
-  return m_Pimpl->m_Parameters.max_linesearch;
+  return m_Parameters.max_linesearch;
 }
 
 template <typename TInternalComputationValueType>
@@ -469,7 +460,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetMinimumLineSearchStep(
   LBFGS2Optimizerv4Template::PrecisionType step)
 {
-  m_Pimpl->m_Parameters.min_step = step;
+  m_Parameters.min_step = step;
   this->Modified();
 }
 
@@ -477,7 +468,7 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetMinimumLineSearchStep() const
 {
-  return m_Pimpl->m_Parameters.min_step;
+  return m_Parameters.min_step;
 }
 
 template <typename TInternalComputationValueType>
@@ -485,7 +476,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetMaximumLineSearchStep(
   LBFGS2Optimizerv4Template::PrecisionType step)
 {
-  m_Pimpl->m_Parameters.max_step = step;
+  m_Parameters.max_step = step;
 
   this->Modified();
 }
@@ -494,7 +485,7 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetMaximumLineSearchStep() const
 {
-  return m_Pimpl->m_Parameters.max_step;
+  return m_Parameters.max_step;
 }
 
 template <typename TInternalComputationValueType>
@@ -502,7 +493,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetLineSearchAccuracy(
   LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType ftol)
 {
-  m_Pimpl->m_Parameters.ftol = ftol;
+  m_Parameters.ftol = ftol;
 
   this->Modified();
 }
@@ -510,7 +501,7 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetLineSearchAccuracy() const
 {
-  return m_Pimpl->m_Parameters.ftol;
+  return m_Parameters.ftol;
 }
 
 template <typename TInternalComputationValueType>
@@ -518,7 +509,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetWolfeCoefficient(
   LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType wc)
 {
-  m_Pimpl->m_Parameters.wolfe = wc;
+  m_Parameters.wolfe = wc;
   this->Modified();
 }
 
@@ -526,7 +517,7 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetWolfeCoefficient() const
 {
-  return m_Pimpl->m_Parameters.wolfe;
+  return m_Parameters.wolfe;
 }
 
 template <typename TInternalComputationValueType>
@@ -534,7 +525,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetLineSearchGradientAccuracy(
   LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType gtol)
 {
-  m_Pimpl->m_Parameters.gtol = gtol;
+  m_Parameters.gtol = gtol;
   this->Modified();
 }
 
@@ -542,7 +533,7 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetLineSearchGradientAccuracy() const
 {
-  return m_Pimpl->m_Parameters.gtol;
+  return m_Parameters.gtol;
 }
 
 
@@ -551,7 +542,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetMachinePrecisionTolerance(
   LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType xtol)
 {
-  m_Pimpl->m_Parameters.xtol = xtol;
+  m_Parameters.xtol = xtol;
   this->Modified();
 }
 
@@ -559,7 +550,7 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetMachinePrecisionTolerance() const
 {
-  return m_Pimpl->m_Parameters.xtol;
+  return m_Parameters.xtol;
 }
 
 template <typename TInternalComputationValueType>
@@ -567,7 +558,7 @@ void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetOrthantwiseCoefficient(
   LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType orthant_c)
 {
-  m_Pimpl->m_Parameters.orthantwise_c = orthant_c;
+  m_Parameters.orthantwise_c = orthant_c;
   this->Modified();
 }
 
@@ -575,14 +566,14 @@ template <typename TInternalComputationValueType>
 typename LBFGS2Optimizerv4Template<TInternalComputationValueType>::PrecisionType
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetOrthantwiseCoefficient() const
 {
-  return m_Pimpl->m_Parameters.orthantwise_c;
+  return m_Parameters.orthantwise_c;
 }
 
 template <typename TInternalComputationValueType>
 void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetOrthantwiseStart(int start)
 {
-  m_Pimpl->m_Parameters.orthantwise_start = start;
+  m_Parameters.orthantwise_start = start;
   this->Modified();
 }
 
@@ -590,14 +581,14 @@ template <typename TInternalComputationValueType>
 int
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetOrthantwiseStart() const
 {
-  return m_Pimpl->m_Parameters.orthantwise_start;
+  return m_Parameters.orthantwise_start;
 }
 
 template <typename TInternalComputationValueType>
 void
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::SetOrthantwiseEnd(int end)
 {
-  m_Pimpl->m_Parameters.orthantwise_end = end;
+  m_Parameters.orthantwise_end = end;
   this->Modified();
 }
 
@@ -605,7 +596,7 @@ template <typename TInternalComputationValueType>
 int
 LBFGS2Optimizerv4Template<TInternalComputationValueType>::GetOrthantwiseEnd() const
 {
-  return m_Pimpl->m_Parameters.orthantwise_end;
+  return m_Parameters.orthantwise_end;
 }
 
 
diff --git a/Modules/Numerics/Optimizersv4/src/itkLBFGS2Optimizerv4.cxx b/Modules/Numerics/Optimizersv4/src/itkLBFGS2Optimizerv4.cxx
index 8dd1d28c1da..1c2eea9aa0e 100644
--- a/Modules/Numerics/Optimizersv4/src/itkLBFGS2Optimizerv4.cxx
+++ b/Modules/Numerics/Optimizersv4/src/itkLBFGS2Optimizerv4.cxx
@@ -43,3 +43,5 @@ operator<<(std::ostream & out, const LBFGS2Optimizerv4Enums::LineSearchMethod va
     }
   }();
 }
+
+} // end namespace itk