Added FDEM simulation code

Author: Tsuchijo

simpegtorch/electromagnetics/FDEM/simulation.py

@@ -0,0 +1,70 @@
+import torch
+from simpegtorch.torchmatsolver import batched_mumps_solve, batched_sparse_solve
+
+from simpegtorch.discretize import TensorMesh
+
+# from simpegtorch.discretize.utils import sdiag
+
+
+class BaseFDEMSimulation:
+    """
+    Base class for FDEM simulations.
+    """
+
+    def __init__(self, mesh: TensorMesh, survey=None, **kwargs):
+        self.mesh = mesh
+        self.survey = survey
+
+    def getRHS():
+        """
+        Get the right-hand side (RHS) vector for the simulation.
+        This method should be implemented in derived classes.
+        """
+        raise NotImplementedError("getRHS must be implemented in derived classes.")
+
+    def getA():
+        """
+        Get the system matrix (A) for the simulation.
+        This method should be implemented in derived classes.
+        """
+        raise NotImplementedError("getA must be implemented in derived classes.")
+
+    def fields(self, m):
+        """
+        Compute the fields for the given model parameters.
+
+        Parameters
+        ----------
+        m : torch.Tensor
+            Model parameters.
+
+        Returns
+        -------
+        torch.Tensor
+            Computed fields.
+        """
+        A = self.getA(m)
+        rhs = self.getRHS(m)
+
+        # Solve the system of equations
+        if isinstance(A, torch.sparse.FloatTensor):
+            return batched_sparse_solve(A, rhs)
+        else:
+            return batched_mumps_solve(A, rhs)
+
+    def dpred(self, m):
+        """
+        Compute the predicted data for the given model parameters.
+
+        Parameters
+        ----------
+        m : torch.Tensor
+            Model parameters.
+
+        Returns
+        -------
+        torch.Tensor
+            Predicted data.
+        """
+        fields = self.fields(m)
+        return self.survey.get_data(fields) if self.survey else fields