[HOTFIX] Wrap torch abs

Author: Leguark

gempy_engine/core/backend_tensor.py

@@ -175,6 +175,7 @@ def _transpose(tensor, axes=None):
         cls.tfnp.concatenate = _concatenate
         cls.tfnp.transpose = _transpose
         cls.tfnp.geomspace = lambda start, stop, step: torch.logspace(start, stop, step, base=10)
+        cls.tfnp.abs = lambda tensor, dtype: tensor.abs().type(dtype)
 
     @classmethod
     def _wrap_pykeops_functions(cls):