[WIP] Adding basic implementation of gravity

Author: Leguark

gempy_probability/modules/likelihoods/__init__.py

@@ -1 +1,2 @@
-from _apparent_thickness import apparent_thickness_likelihood
+from _apparent_thickness import apparent_thickness_likelihood
+from _gravity_inv import gravity_inversion_likelihood

gempy_probability/modules/likelihoods/_apparent_thickness.py

@@ -5,6 +5,8 @@
 def apparent_thickness_likelihood(model_solutions: gp.data.Solutions) -> torch.Tensor:
     """
     This function computes the thickness of the geological layer.
+    
+    Notes: This is not completed
     """
     simulated_well = model_solutions.octrees_output[0].last_output_center.custom_grid_values
     thickness = simulated_well.sum()

gempy_probability/modules/likelihoods/_gravity_inv.py

@@ -0,0 +1,9 @@
+import pyro
+import torch
+import gempy as gp
+
+def gravity_inversion_likelihood(model_solutions: gp.data.Solutions) -> torch.Tensor:
+    simulated_geophysics = model_solutions.gravity
+    pyro.deterministic(r'$\mu_{gravity}$', simulated_geophysics)
+    
+    return simulated_geophysics