Merge pull request #1449 from pybamm-team/issue-1429-simplifications

Issue 1429 simplifications

CHANGELOG.md

@@ -7,6 +7,8 @@
 ## Optimizations
 
 -   Improved how the CasADi solver's "safe" mode finds events ([#1450](https://github.com/pybamm-team/PyBaMM/pull/1450))
+-   Perform more automatic simplifications of the expression tree ([#1449](https://github.com/pybamm-team/PyBaMM/pull/1449))
+-   Reduce time taken to hash a sparse `Matrix` object ([#1449](https://github.com/pybamm-team/PyBaMM/pull/1449))
 
 # [v0.4.0](https://github.com/pybamm-team/PyBaMM/tree/v0.4.0) - 2021-03-28
 

docs/source/expression_tree/unary_operator.rst

@@ -28,7 +28,7 @@ Unary Operators
 .. autoclass:: pybamm.Laplacian
   :members:
 
-.. autoclass:: pybamm.Gradient_Squared
+.. autoclass:: pybamm.GradientSquared
   :members:
 
 .. autoclass:: pybamm.Mass

pybamm/discretisations/discretisation.py

@@ -828,6 +828,7 @@ def process_symbol(self, symbol):
             discretised_symbol = self._process_symbol(symbol)
             self._discretised_symbols[symbol.id] = discretised_symbol
             discretised_symbol.test_shape()
+
             # Assign mesh as an attribute to the processed variable
             if symbol.domain != []:
                 discretised_symbol.mesh = self.mesh.combine_submeshes(*symbol.domain)
@@ -883,7 +884,7 @@ def _process_symbol(self, symbol):
             elif isinstance(symbol, pybamm.Laplacian):
                 return child_spatial_method.laplacian(child, disc_child, self.bcs)
 
-            elif isinstance(symbol, pybamm.Gradient_Squared):
+            elif isinstance(symbol, pybamm.GradientSquared):
                 return child_spatial_method.gradient_squared(
                     child, disc_child, self.bcs
                 )
@@ -1030,7 +1031,6 @@ def _process_symbol(self, symbol):
         elif isinstance(symbol, pybamm.Concatenation):
             new_children = [self.process_symbol(child) for child in symbol.children]
             new_symbol = spatial_method.concatenation(new_children)
-
             return new_symbol
 
         elif isinstance(symbol, pybamm.InputParameter):

pybamm/expression_tree/array.py

@@ -36,13 +36,14 @@ def __init__(
         auxiliary_domains=None,
         entries_string=None,
     ):
+        # if
         if isinstance(entries, list):
             entries = np.array(entries)
         if entries.ndim == 1:
             entries = entries[:, np.newaxis]
         if name is None:
             name = "Array of shape {!s}".format(entries.shape)
-        self._entries = entries
+        self._entries = entries.astype(float)
         # Use known entries string to avoid re-hashing, where possible
         self.entries_string = entries_string
         super().__init__(name, domain=domain, auxiliary_domains=auxiliary_domains)
@@ -75,14 +76,19 @@ def entries_string(self, value):
         else:
             entries = self._entries
             if issparse(entries):
-                self._entries_string = str(entries.__dict__)
+                dct = entries.__dict__
+                self._entries_string = ["shape", str(dct["_shape"])]
+                for key in ["data", "indices", "indptr"]:
+                    self._entries_string += [key, dct[key].tobytes()]
+                self._entries_string = tuple(self._entries_string)
+                # self._entries_string = str(entries.__dict__)
             else:
-                self._entries_string = entries.tobytes()
+                self._entries_string = (entries.tobytes(),)
 
     def set_id(self):
         """ See :meth:`pybamm.Symbol.set_id()`. """
         self._id = hash(
-            (self.__class__, self.name, self.entries_string) + tuple(self.domain)
+            (self.__class__, self.name) + self.entries_string + tuple(self.domain)
         )
 
     def _jac(self, variable):