Initialize variables at declaration if it improves readability (#4117)

* init some variables at declaration

* make code more readable

* avoid lossy function result cast

* Update Source/Initialization/WarpXInitData.cpp

Co-authored-by: Weiqun Zhang <WeiqunZhang@lbl.gov>

* replace with equality

* Revert "replace with equality"

This reverts commit e3164f9e053d345b153d770ae107a7f68c4bb260.

* Update Source/Diagnostics/ComputeDiagFunctors/ParticleReductionFunctor.cpp

Co-authored-by: Weiqun Zhang <WeiqunZhang@lbl.gov>

---------

Co-authored-by: Weiqun Zhang <WeiqunZhang@lbl.gov>

1 files changed, 4 insertions, 7 deletions

diff --git a/Source/Diagnostics/ReducedDiags/ParticleEnergy.cpp b/Source/Diagnostics/ReducedDiags/ParticleEnergy.cpp
index 47b90e099..ebf280e8f 100644
--- a/Source/Diagnostics/ReducedDiags/ParticleEnergy.cpp
+++ b/Source/Diagnostics/ReducedDiags/ParticleEnergy.cpp
@@ -99,9 +99,6 @@ void ParticleEnergy::ComputeDiags (int step)
     // Get number of species
     const int nSpecies = mypc.nSpecies();
 
-    // Some useful offsets to fill m_data below
-    int offset_total_species, offset_mean_species, offset_mean_all;
-
     amrex::Real Wtot = 0.0_rt;
 
     // Loop over species
@@ -169,7 +166,7 @@ void ParticleEnergy::ComputeDiags (int step)
         // Offset:
         // 1 value of total energy for all  species +
         // 1 value of total energy for each species
-        offset_total_species = 1 + i_s;
+        const int offset_total_species = 1 + i_s;
         m_data[offset_total_species] = Etot;
 
         // Offset:
@@ -177,7 +174,7 @@ void ParticleEnergy::ComputeDiags (int step)
         // 1 value of total energy for each species +
         // 1 value of mean  energy for all  species +
         // 1 value of mean  energy for each species
-        offset_mean_species = 1 + nSpecies + 1 + i_s;
+        const int offset_mean_species = 1 + nSpecies + 1 + i_s;
         if (Ws > std::numeric_limits<Real>::min())
         {
             m_data[offset_mean_species] = Etot / Ws;
@@ -197,14 +194,14 @@ void ParticleEnergy::ComputeDiags (int step)
         // Offset:
         // 1 value of total energy for all  species +
         // 1 value of total energy for each species
-        offset_total_species = 1 + i_s;
+        const int offset_total_species = 1 + i_s;
         m_data[0] += m_data[offset_total_species];
     }
 
     // Total mean energy. Offset:
     // 1 value of total energy for all  species +
     // 1 value of total energy for each species
-    offset_mean_all = 1 + nSpecies;
+    const int offset_mean_all = 1 + nSpecies;
     if (Wtot > std::numeric_limits<Real>::min())
     {
         m_data[offset_mean_all] = m_data[0] / Wtot;