feat(solver): added callback functions to solver in C++ and python

tests/python/test.py

@@ -3,6 +3,7 @@ from gridfire.solver import DirectNetworkSolver
 from gridfire.type import NetIn
 
 from fourdst.composition import Composition
+from fourdst.atomic import species
 
 symbols : list[str] = ["H-1", "He-3", "He-4", "C-12", "N-14", "O-16", "Ne-20", "Mg-24"]
 X : list[float]     = [0.708, 2.94e-5, 0.276, 0.003, 0.0011, 9.62e-3, 1.62e-3, 5.16e-4]
@@ -19,7 +20,7 @@ netIn = NetIn()
 netIn.composition = comp
 netIn.temperature = 1.5e7
 netIn.density = 1.6e2
-netIn.tMax = 1e-9
+netIn.tMax = 4e17
 netIn.dt0 = 1e-12
 
 baseEngine = GraphEngine(netIn.composition, 2)
@@ -31,6 +32,15 @@ adaptiveEngine = AdaptiveEngineView(qseEngine)
 
 solver = DirectNetworkSolver(adaptiveEngine)
 
+
+def callback(context):
+    H1Index = context.engine.getSpeciesIndex(species["H-1"])
+    He4Index = context.engine.getSpeciesIndex(species["He-4"])
+    C12ndex = context.engine.getSpeciesIndex(species["C-12"])
+    Mgh24ndex = context.engine.getSpeciesIndex(species["Mg-24"])
+    print(f"Time: {context.t}, H-1: {context.state[H1Index]}, He-4: {context.state[He4Index]}, C-12: {context.state[C12ndex]}, Mg-24: {context.state[Mgh24ndex]}")
+
+# solver.set_callback(callback)
 results = solver.evaluate(netIn)
 
 print(f"Final H-1 mass fraction {results.composition.getMassFraction("H-1")}")