Fix shadowed variable in mapillary/opensfm/opensfm/src/third_party/ak…

…aze/lib/nldiffusion_functions.cpp

Summary:
Our upcoming compiler upgrade will require us not to have shadowed variables. Such variables have a _high_ bug rate and reduce readability, so we would like to avoid them even if the compiler was not forcing us to do so.

This codemod attempts to fix an instance of a shadowed variable. Please review with care: if it's failed the result will be a silent bug.

**What's a shadowed variable?**

Shadowed variables are variables in an inner scope with the same name as another variable in an outer scope. Having the same name for both variables might be semantically correct, but it can make the code confusing to read! It can also hide subtle bugs.

This diff fixes such an issue by renaming the variable.

 - If you approve of this diff, please use the "Accept & Ship" button :-)

Reviewed By: palmje

Differential Revision: D64398715

fbshipit-source-id: 5a49263b83945d723e9f3046fb13e260e9c6af11

opensfm/src/third_party/akaze/lib/nldiffusion_functions.cpp

@@ -299,22 +299,22 @@ void nld_step_scalar(cv::Mat& Ld, const cv::Mat& c, cv::Mat& Lstep, const float
     Lstep_row = Lstep.ptr<float>(i);
 
     float xpos_2 = (c_row_2[0]+c_row_2[1])*(Ld_row_2[1]-Ld_row_2[0]);
-    float ypos = (c_row_2[0]+c_row_p_2[0])*(Ld_row_p_2[0]-Ld_row_2[0]);
+    float ypos_2 = (c_row_2[0]+c_row_p_2[0])*(Ld_row_p_2[0]-Ld_row_2[0]);
     float yneg = (c_row_m[0]+c_row_2[0])*(Ld_row_2[0]-Ld_row_m[0]);
-    Lstep_row[0] = 0.5*stepsize*(xpos_2+ypos-yneg);
+    Lstep_row[0] = 0.5*stepsize*(xpos_2+ypos_2-yneg);
 
-    float xneg = (c_row_2[Lstep.cols-2]+c_row_2[Lstep.cols-1])*(Ld_row_2[Lstep.cols-1]-Ld_row_2[Lstep.cols-2]);
-    ypos = (c_row_2[Lstep.cols-1]+c_row_p_2[Lstep.cols-1])*(Ld_row_p_2[Lstep.cols-1]-Ld_row_2[Lstep.cols-1]);
+    float xneg_2 = (c_row_2[Lstep.cols-2]+c_row_2[Lstep.cols-1])*(Ld_row_2[Lstep.cols-1]-Ld_row_2[Lstep.cols-2]);
+    ypos_2 = (c_row_2[Lstep.cols-1]+c_row_p_2[Lstep.cols-1])*(Ld_row_p_2[Lstep.cols-1]-Ld_row_2[Lstep.cols-1]);
     yneg = (c_row_m[Lstep.cols-1]+c_row_2[Lstep.cols-1])*(Ld_row_2[Lstep.cols-1]-Ld_row_m[Lstep.cols-1]);
-    Lstep_row[Lstep.cols-1] = 0.5*stepsize*(-xneg+ypos-yneg);
+    Lstep_row[Lstep.cols-1] = 0.5*stepsize*(-xneg_2+ypos_2-yneg);
   }
 
   // Ld = Ld + Lstep
   for (int y = 0; y < Lstep.rows; y++) {
-    float* Ld_row = Ld.ptr<float>(y);
-    float* Lstep_row = Lstep.ptr<float>(y);
-    for (int x = 0; x < Lstep.cols; x++) {
-      Ld_row[x] = Ld_row[x] + Lstep_row[x];
+    float* Ld_row_2 = Ld.ptr<float>(y);
+    float* Lstep_row_2 = Lstep.ptr<float>(y);
+    for (int x_2 = 0; x_2 < Lstep.cols; x_2++) {
+      Ld_row_2[x_2] = Ld_row_2[x_2] + Lstep_row_2[x_2];
     }
   }
 }