From 21df56e1646789210d2391ff8386119fa065ff1c Mon Sep 17 00:00:00 2001
From: Florian OMNES <26088210+flomnes@users.noreply.github.com>
Date: Wed, 13 Dec 2023 13:32:46 +0100
Subject: [PATCH 1/2] Small code improvement in solver_utils.cpp

---
 src/solver/simulation/solver_utils.cpp | 37 +++++++++++++-------------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/src/solver/simulation/solver_utils.cpp b/src/solver/simulation/solver_utils.cpp
index 32449af22b..fc425ee40c 100644
--- a/src/solver/simulation/solver_utils.cpp
+++ b/src/solver/simulation/solver_utils.cpp
@@ -16,14 +16,11 @@ static const std::string optimizationTimeFilename
 static const std::string updateTimeFilename
   = std::string("optimization") + SEP + "update-durations.txt";
 
-static std::string to_scientific(const double d)
+static std::ostream& toScientific(std::ostream& os)
 {
-    std::ostringstream stream;
-    stream << std::scientific;
-    stream << std::setprecision(14);
-    stream << d;
-
-    return stream.str();
+    os << std::scientific;
+    os << std::setprecision(14);
+    return os;
 }
 
 namespace Antares::Solver::Simulation
@@ -100,18 +97,20 @@ void annualCostsStatistics::writeSystemCostToOutput(IResultWriter& writer)
 
 void annualCostsStatistics::writeCriterionCostsToOutput(IResultWriter& writer) const
 {
-    std::string buffer;
-    buffer += to_scientific(criterionCost1.costAverage) + "\n";
-    buffer += to_scientific(criterionCost1.costStdDeviation) + "\n";
-    buffer += to_scientific(criterionCost1.costMin) + "\n";
-    buffer += to_scientific(criterionCost1.costMax) + "\n";
-
-    buffer += to_scientific(criterionCost2.costAverage) + "\n";
-    buffer += to_scientific(criterionCost2.costStdDeviation) + "\n";
-    buffer += to_scientific(criterionCost2.costMin) + "\n";
-    buffer += to_scientific(criterionCost2.costMax) + "\n";
-
-    writer.addEntryFromBuffer(criterionsCostsFilename, buffer);
+    using std::endl;
+    std::ostringstream buffer;
+    buffer << toScientific
+           << criterionCost1.costAverage << endl
+           << criterionCost1.costStdDeviation << endl
+           << criterionCost1.costMin << endl
+           << criterionCost1.costMax << endl
+           << criterionCost2.costAverage << endl
+           << criterionCost2.costStdDeviation << endl
+           << criterionCost2.costMin << endl
+           << criterionCost2.costMax << endl;
+
+    std::string s = buffer.str(); // TODO allow std::string&& in addEntryFromBuffer
+    writer.addEntryFromBuffer(criterionsCostsFilename, s);
 }
 
 void annualCostsStatistics::writeUpdateTimes(IResultWriter& writer) const

From 59d7d89aa38f0c7ff2e5d9dcc0c11d097ae82ced Mon Sep 17 00:00:00 2001
From: Florian OMNES <26088210+flomnes@users.noreply.github.com>
Date: Wed, 13 Dec 2023 13:36:29 +0100
Subject: [PATCH 2/2] Simplify a bit more

---
 src/solver/simulation/solver_utils.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/solver/simulation/solver_utils.cpp b/src/solver/simulation/solver_utils.cpp
index fc425ee40c..a9f539860e 100644
--- a/src/solver/simulation/solver_utils.cpp
+++ b/src/solver/simulation/solver_utils.cpp
@@ -18,9 +18,7 @@ static const std::string updateTimeFilename
 
 static std::ostream& toScientific(std::ostream& os)
 {
-    os << std::scientific;
-    os << std::setprecision(14);
-    return os;
+    return os << std::scientific << std::setprecision(14);
 }
 
 namespace Antares::Solver::Simulation