ENH: Add JSON export and CSV export support for monte carlo result

monte_carlo_test.outputs.txt

@@ -0,0 +1,3 @@
+{"x_impact": 261.11227152428785, "out_of_rail_velocity": 21.263362678403276, "lateral_surface_wind": 0.0, "impact_velocity": -5.5974307833687975, "apogee_y": 185.02990620611027, "apogee": 4090.397476048397, "max_mach_number": 0.7362805444720003, "out_of_rail_stability_margin": 2.315089166308985, "apogee_x": 222.39281714255011, "t_final": 258.96490133727735, "frontal_surface_wind": 0.0, "apogee_time": 24.189875450232726, "initial_stability_margin": 2.233761459523716, "y_impact": 216.94920645594468, "out_of_rail_time": 0.3526399202369637, "index": 1}
+{"x_impact": 484.2520018225589, "out_of_rail_velocity": 23.043449951089155, "lateral_surface_wind": 0.0, "impact_velocity": -5.638698448227493, "apogee_y": 374.1333818596774, "apogee": 4933.3951884764765, "max_mach_number": 0.8972012428141698, "out_of_rail_stability_margin": 2.3686077590907453, "apogee_x": 421.4330962089096, "t_final": 300.9720229351123, "frontal_surface_wind": 0.0, "apogee_time": 27.281168813699697, "initial_stability_margin": 2.2964923844396727, "y_impact": 429.3662643361925, "out_of_rail_time": 0.32514873530416133, "index": 2}
+{"x_impact": 372.6625337978357, "out_of_rail_velocity": 18.904312773708973, "lateral_surface_wind": 0.0, "impact_velocity": -5.568722088369098, "apogee_y": 224.41013464039185, "apogee": 3401.4185587371117, "max_mach_number": 0.6049423853841714, "out_of_rail_stability_margin": 2.1710531802525574, "apogee_x": 317.7795912292856, "t_final": 229.8195457110126, "frontal_surface_wind": 0.0, "apogee_time": 21.524782290759216, "initial_stability_margin": 2.0781643782173873, "y_impact": 262.9697158122671, "out_of_rail_time": 0.3969987568929141, "index": 3}

rocketpy/simulation/monte_carlo.py

@@ -1150,6 +1150,82 @@ def export_ellipses_to_kml(  # pylint: disable=too-many-statements
 
         kml.save(filename)
 
+    def export_json(
+            self,
+            filename,
+            indent_size = 4
+    ):
+        """
+    Export Monte Carlo results into a JSON file.
+
+    The exported data reflects exactly what is stored inside ``self.results``.
+    Depending on how the MonteCarlo object was populated, values may be either
+    lists (when results come from running Monte Carlo simulations) or scalars
+    (when results are imported from previously saved output summaries).
+
+    Parameters
+    ----------
+    filename : str
+        Path to the JSON file that will be created. If the file already exists,
+        it will be overwritten.
+    indent_size : int, optional
+        Number of spaces used for indentation in the generated JSON file.
+        Defaults to 4.
+
+    Notes
+    -----
+    This function only exports the data already contained inside
+    ``self.results``. No computations are performed during export. Users
+    should call ``simulate()`` or ``import_results()`` before exporting.
+
+    Examples
+    --------
+    Run new Monte Carlo simulations and export results::
+
+        mc = MonteCarlo(environment=env, rocket=rocket, flight=flight)
+        mc.simulate(20)
+        mc.export_json("results.json")
+
+    Export results previously loaded from file::
+
+        mc = MonteCarlo(environment=env, rocket=rocket, flight=flight)
+        mc.import_results("sample.outputs.txt")
+        mc.export_json("summary.json")
+    """
+        if filename is None:
+            return ValueError("A valid filename to be provided !!")
+
+        if not filename.lower().endswith(".json"):
+            return ValueError("filename should end with .json")
+
+        if not self.results or len(self.results) == 0:
+            raise RuntimeError("Monte Carlo test simulations to be performed ")
+
+        export_dictionary = {}
+
+        for key in self.results:
+            value_list = self.results[key]
+
+            converted_values = []
+
+            for value in value_list:
+                if isinstance(value, np.generic):
+                    converted_values.append(value.float())
+
+                else:
+                    converted_values = value
+
+            export_dictionary[key] = converted_values
+
+        try:
+            with open(filename, "w", encoding = "utf-8") as file:
+                json.dump(export_dictionary, file, indent = indent_size)
+
+        except (TypeError, OSError) as e:
+            print(f"Error writing JSON: {e}")
+
+        return
+
     def info(self):
         """
         Print information about the Monte Carlo simulation.

temp_test_output.json

@@ -0,0 +1,18 @@
+{
+    "x_impact": 372.6625337978357,
+    "out_of_rail_velocity": 18.904312773708973,
+    "lateral_surface_wind": 0.0,
+    "impact_velocity": -5.568722088369098,
+    "apogee_y": 224.41013464039185,
+    "apogee": 3401.4185587371117,
+    "max_mach_number": 0.6049423853841714,
+    "out_of_rail_stability_margin": 2.1710531802525574,
+    "apogee_x": 317.7795912292856,
+    "t_final": 229.8195457110126,
+    "frontal_surface_wind": 0.0,
+    "apogee_time": 21.524782290759216,
+    "initial_stability_margin": 2.0781643782173873,
+    "y_impact": 262.9697158122671,
+    "out_of_rail_time": 0.3969987568929141,
+    "index": 3
+}

tests/test_monte_carlo_export.py

@@ -0,0 +1,28 @@
+import os
+import json
+
+def test_json_export(monte_carlo_calisto):
+    mc = monte_carlo_calisto
+    mc.simulate(3)
+
+    filename = "temp_test_output.json"
+    mc.export_json(filename)
+
+    assert os.path.exists(filename)
+
+    with open(filename, "r") as f:
+        data = json.load(f)
+
+    # Assert dictionary keys exist
+    assert len(data.keys()) > 0
+
+    # Check that at least one key corresponds to a list of simulation results
+    list_keys = [k for k, v in data.items() if isinstance(v, list)]
+
+    # There must be at least 1 Monte Carlo-dependent field
+    assert len(list_keys) > 0
+
+    first_list_key = list_keys[0]
+    assert len(data[first_list_key]) == 3
+
+    os.remove(filename)