From fc60d5aeaa849ac7e73badcdfff803cb50309158 Mon Sep 17 00:00:00 2001
From: Niels Dekker <N.Dekker@lumc.nl>
Date: Wed, 13 May 2026 18:55:36 +0200
Subject: [PATCH] STYLE: Reduce scope of jacobian in
 ThreadedComputeDerivativeLowMemory

Following C++ Core Guidelines, Jul 8, 2025, "Keep scopes small", https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#res-scope

Possibly slightly related to issue https://github.com/SuperElastix/elastix/issues/1443 "Suspicious `for`-`while`-loops in ParzenWindowMutualInformationImageToImageMetric"
---
 .../itkParzenWindowMutualInformationImageToImageMetric.hxx      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Components/Metrics/AdvancedMattesMutualInformation/itkParzenWindowMutualInformationImageToImageMetric.hxx b/Components/Metrics/AdvancedMattesMutualInformation/itkParzenWindowMutualInformationImageToImageMetric.hxx
index 6f8b58d33..59982f12a 100644
--- a/Components/Metrics/AdvancedMattesMutualInformation/itkParzenWindowMutualInformationImageToImageMetric.hxx
+++ b/Components/Metrics/AdvancedMattesMutualInformation/itkParzenWindowMutualInformationImageToImageMetric.hxx
@@ -479,9 +479,9 @@ ParzenWindowMutualInformationImageToImageMetric<TFixedImage, TMovingImage>::Thre
 #endif
 
       /** If desired, apply the technique introduced by Tustison. */
-      TransformJacobianType jacobian;
       if (this->GetUseJacobianPreconditioning())
       {
+        TransformJacobianType jacobian;
         this->EvaluateTransformJacobian(fixedPoint, jacobian, nzji);
 
         this->ComputeJacobianPreconditioner(jacobian, nzji, jacobianPreconditioner, preconditioningDivisor);