Model that allows interpolation from one mesh to another.

SimPEG/Model.py

@@ -174,6 +174,56 @@ class Vertical1DModel(BaseModel):
                     ), shape=(repNum, 1))
         return sp.kron(sp.identity(self.nP), repVec)
 
+class Mesh2Mesh(BaseModel):
+    """
+        Takes a model on one mesh are translates it to another mesh.
+
+        .. plot::
+
+            from SimPEG import *
+            M = Mesh.TensorMesh([100,100])
+            h1 = Utils.meshTensors(((7,6,1.5),(10,6),(7,6,1.5)))
+            h1 = h1/h1.sum()
+            M2 = Mesh.TensorMesh([h1,h1])
+            V = Utils.ModelBuilder.randomModel(M.vnC, seed=79, its=50)
+            v = Utils.mkvc(V)
+            modh = Model.Mesh2Mesh([M,M2])
+            modH = Model.Mesh2Mesh([M2,M])
+            H = modH.transform(v)
+            h = modh.transform(H)
+            ax = plt.subplot(131)
+            M.plotImage(v, ax=ax)
+            ax.set_title('Fine Mesh (Original)')
+            ax = plt.subplot(132)
+            M2.plotImage(H,clim=[0,1],ax=ax)
+            ax.set_title('Course Mesh')
+            ax = plt.subplot(133)
+            M.plotImage(h,clim=[0,1],ax=ax)
+            ax.set_title('Fine Mesh (Interpolated)')
+
+    """
+
+    def __init__(self, meshes, **kwargs):
+        Utils.setKwargs(self, **kwargs)
+
+        assert type(meshes) is list, "meshes must be a list of two meshes"
+        assert len(meshes) == 2, "meshes must be a list of two meshes"
+        assert meshes[0].dim == meshes[1].dim, """The two meshes must be the same dimension"""
+
+        self.mesh  = meshes[0]
+        self.mesh2 = meshes[1]
+
+        self.P = self.mesh2.getInterpolationMat(self.mesh.gridCC,'CC',zerosOutside=True)
+
+    @property
+    def nP(self):
+        """Number of parameters in the model."""
+        return self.mesh2.nC
+    def transform(self, m):
+        return self.P*m
+    def transformDeriv(self, m):
+        return self.P
+
 class ComboModel(BaseModel):
     """Combination of various models."""
 

SimPEG/Tests/test_model.py

@@ -11,7 +11,8 @@ class ModelTests(unittest.TestCase):
 
         a = np.array([1, 1, 1])
         b = np.array([1, 2])
-        self.mesh2 = Mesh.TensorMesh([a, b], np.array([3, 5]))
+        self.mesh2 = Mesh.TensorMesh([a, b], x0=np.array([3, 5]))
+        self.mesh22 = Mesh.TensorMesh([b, a], x0=np.array([3, 5]))
 
     def test_modelTransforms(self):
         for M in dir(Model):
@@ -22,6 +23,10 @@ class ModelTests(unittest.TestCase):
                 continue
             self.assertTrue(model.test())
 
+    def test_Mesh2MeshModel(self):
+        model = Model.Mesh2Mesh([self.mesh22, self.mesh2])
+        self.assertTrue(model.test())
+
     def test_comboModels(self):
         combos = [(Model.LogModel, Model.Vertical1DModel)]
         for combo in combos: