Adding python bindings and a helper setter/getter object in python to… (#5876)

… expose the density floor and substep parameters that can be adjusted
at runtime.

---------

Signed-off-by: S. Eric Clark <[email protected]>

Author: clarkse

Python/pywarpx/HybridPICModel.py

@@ -1,12 +1,48 @@
-# Copyright 2023 The WarpX Community
+# Copyright 2023-2025 The WarpX Community
 #
 # This file is part of WarpX.
 #
 # Authors: Roelof Groenewald (TAE Technologies)
+#          S. Eric Clark (Helion Energy)
 #
 # License: BSD-3-Clause-LBNL
 
+from ._libwarpx import libwarpx
 from .Bucket import Bucket
 
 hybridpicmodel = Bucket("hybrid_pic_model")
 external_vector_potential = Bucket("external_vector_potential")
+
+
+class HybridPICModel(object):
+    """HybridPICModel
+
+    Description: This is an accessor object to be able to vary parameters
+    in the WarpX HybridPICModel class. This can be useful for adjusting parameters
+    like the density floor or number of substeps taken dynamically. This will be implemented
+    as a selection of parameters that can be adjusted at runtime in installed callbacks.
+    """
+
+    def __init__(self):
+        # Nothing to be done since this is a wrapper object
+        pass
+
+    @property
+    def substeps(self):
+        warpx = libwarpx.libwarpx_so.get_instance()
+        return warpx.get_hybrid_pic_substeps()
+
+    @substeps.setter
+    def substeps(self, substeps):
+        warpx = libwarpx.libwarpx_so.get_instance()
+        return warpx.set_hybrid_pic_substeps(substeps)
+
+    @property
+    def density_floor(self):
+        warpx = libwarpx.libwarpx_so.get_instance()
+        return warpx.get_hybrid_pic_density_floor()
+
+    @density_floor.setter
+    def density_floor(self, n_floor):
+        warpx = libwarpx.libwarpx_so.get_instance()
+        return warpx.set_hybrid_pic_density_floor(n_floor)

Source/Python/WarpX.cpp

@@ -278,6 +278,33 @@ The physical fields in WarpX have the following naming:
             [] (WarpX& wx) { wx.SynchronizeVelocityWithPosition(); },
             "Synchronize particle velocities and positions."
         )
+        // Add some accessor bindings for the Hybrid Ohm's Law Solver
+        .def("set_hybrid_pic_substeps",
+            [](WarpX& wx, int substeps) {
+                wx.get_pointer_HybridPICModel()->m_substeps = substeps;
+            },
+            py::arg("substeps"),
+            "Sets the number of substeps to take in the hybrid solver."
+        )
+        .def("get_hybrid_pic_substeps",
+            [](WarpX& wx) {
+                return wx.get_pointer_HybridPICModel()->m_substeps;
+            },
+            "Gets the number of substeps taken in the hybrid solver."
+        )
+        .def("set_hybrid_pic_density_floor",
+            [](WarpX& wx, amrex::Real n_floor) {
+                wx.get_pointer_HybridPICModel()->m_n_floor = n_floor;
+            },
+            py::arg("n_floor"),
+            "Sets the density floor to use in the hybrid solver."
+        )
+        .def("get_hybrid_pic_density_floor",
+            [](WarpX& wx) {
+                return wx.get_pointer_HybridPICModel()->m_n_floor;
+            },
+            "Gets the number of substeps to take in the hybrid solver."
+        )
     ;
 
     py::class_<warpx::Config>(m, "Config")