Controlling fixed precision for logging float point values (#775)

* Added an option to file_observer_config to set fixed precision value. * Fixed build failure
open-simulation-platform · Oct 8, 2024 · 5c6e196 · 5c6e196
1 parent 44115de
commit 5c6e196
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Showing 2 changed files with 35 additions and 4 deletions.
diff --git a/include/cosim/observer/file_observer.hpp b/include/cosim/observer/file_observer.hpp
@@ -23,6 +23,7 @@ namespace cosim
 
 class file_observer;
 
+
 /**
  * Configuration options for file_observer.
  */
@@ -88,9 +89,21 @@ class file_observer_config
      */
     static file_observer_config parse(const filesystem::path& configPath);
 
+    /**
+     * Sets fixed precision value for floating point numbers
+     *
+     * \param precision the number of digits after the decimal point
+     */
+    void fixed_precision(const int precision)
+    {
+        precision_ = precision;
+    }
+
 private:
     bool timeStampedFileNames_{true};
     size_t defaultDecimationFactor_{1};
+    int precision_{-1};
+
     std::unordered_map<std::string, std::pair<size_t, std::vector<std::string>>> variablesToLog_;
 
     [[nodiscard]] bool should_log_simulator(const std::string& name) const

diff --git a/src/cosim/observer/file_observer.cpp b/src/cosim/observer/file_observer.cpp
@@ -46,6 +46,7 @@ void clear_file_contents_if_exists(const cosim::filesystem::path& filePath, std:
         fsw.close();
     }
 }
+
 } // namespace
 
 
@@ -60,12 +61,18 @@ class file_observer::slave_value_writer
         initialize_default();
     }
 
-    slave_value_writer(observable* observable, cosim::filesystem::path& logDir, size_t decimationFactor,
-        const std::vector<variable_description>& variables, bool timeStampedFileNames = true)
+    slave_value_writer(
+        observable* observable, 
+        cosim::filesystem::path& logDir, 
+        size_t decimationFactor,
+        const std::vector<variable_description>& variables, 
+        bool timeStampedFileNames = true,
+        const int precision = -1)
         : observable_(observable)
         , logDir_(logDir)
         , decimationFactor_(decimationFactor)
         , timeStampedFileNames_(timeStampedFileNames)
+        , precision_(precision)
     {
         initialize_config(variables);
     }
@@ -301,10 +308,19 @@ class file_observer::slave_value_writer
     void persist()
     {
         std::stringstream ss;
+        const auto defaultPrecision = ss.precision();
+
         if (fsw_.is_open()) {
 
             for (const auto& [stepCount, times] : timeSamples_) {
-                ss << times << "," << stepCount;
+                if (precision_ > -1) {
+                    ss.precision(defaultPrecision);
+                    ss << times << "," << stepCount;
+                    ss.precision(precision_);
+                    ss << std::fixed;
+                } else {
+                    ss << times << "," << stepCount;
+                }
 
                 if (realSamples_.count(stepCount)) write<double>(realSamples_[stepCount], ss);
                 if (intSamples_.count(stepCount)) write<int>(intSamples_[stepCount], ss);
@@ -340,6 +356,7 @@ class file_observer::slave_value_writer
     std::atomic<bool> recording_ = true;
     std::mutex mutex_;
     bool timeStampedFileNames_ = true;
+    int precision_ = -1;
 };
 
 file_observer::file_observer(const cosim::filesystem::path& logDir, std::optional<file_observer_config> config)
@@ -387,7 +404,8 @@ void file_observer::simulator_added(
                 logDir_,
                 config.decimationFactor,
                 config.variables,
-                config.timeStampedFileNames);
+                config.timeStampedFileNames,
+                config_->precision_);
         } else {
             return;
         }