Merge pull request #1417 from brian-team/deterministic_code

Deterministic code generation

brian2/codegen/codeobject.py

@@ -349,7 +349,7 @@ def create_runner_codeobj(group, code, template_name,
         needed_variables = []
     # Resolve all variables (variables used in the code and variables needed by
     # the template)
-    variables = group.resolve_all(identifiers | set(needed_variables) | set(template_variables),
+    variables = group.resolve_all(sorted(identifiers | set(needed_variables) | set(template_variables)),
                                   # template variables are not known to the user:
                                   user_identifiers=user_identifiers,
                                   additional_variables=additional_variables,

brian2/codegen/generators/cpp_generator.py

@@ -240,7 +240,7 @@ def translate_statement(self, statement):
     def translate_to_read_arrays(self, read, write, indices):
         lines = []
         # index and read arrays (index arrays first)
-        for varname in itertools.chain(indices, read):
+        for varname in itertools.chain(sorted(indices), sorted(read)):
             index_var = self.variable_indices[varname]
             var = self.variables[varname]
             if varname not in write:
@@ -255,7 +255,7 @@ def translate_to_read_arrays(self, read, write, indices):
     def translate_to_declarations(self, read, write, indices):
         lines = []
         # simply declare variables that will be written but not read
-        for varname in write:
+        for varname in sorted(write):
             if varname not in read and varname not in indices:
                 var = self.variables[varname]
                 line = f"{self.c_data_type(var.dtype)} {varname};"
@@ -278,7 +278,7 @@ def translate_to_statements(self, statements, conditional_write_vars):
     def translate_to_write_arrays(self, write):
         lines = []
         # write arrays
-        for varname in write:
+        for varname in sorted(write):
             index_var = self.variable_indices[varname]
             var = self.variables[varname]
             line = f"{self.get_array_name(var)}[{index_var}] = {varname};"

brian2/codegen/generators/cython_generator.py

@@ -132,7 +132,7 @@ def translate_one_statement_sequence(self, statements, scalar=False):
 
     def translate_to_read_arrays(self, read, indices):
         lines = []
-        for varname in itertools.chain(indices, read):
+        for varname in itertools.chain(sorted(indices), sorted(read)):
             var = self.variables[varname]
             index = self.variable_indices[varname]
             arrayname = self.get_array_name(var)
@@ -157,7 +157,7 @@ def translate_to_statements(self, statements, conditional_write_vars):
 
     def translate_to_write_arrays(self, write):
         lines = []
-        for varname in write:
+        for varname in sorted(write):
             index_var = self.variable_indices[varname]
             var = self.variables[varname]
             line = f"{self.get_array_name(var, self.variables)}[{index_var}] = {varname}"

brian2/devices/cpp_standalone/device.py

@@ -13,6 +13,7 @@
 import numbers
 import tempfile
 from distutils import ccompiler
+import zlib
 
 import numpy as np
 
@@ -325,8 +326,8 @@ def get_array_filename(self, var, basedir='results'):
         -------
         filename : str
             A filename of the form
-            ``'results/'+varname+'_'+str(hash(varname))``, where varname is the
-            name returned by `get_array_name`.
+            ``'results/'+varname+'_'+str(zlib.crc32(varname))``, where varname
+            is the name returned by `get_array_name`.
 
         Notes
         -----
@@ -335,7 +336,7 @@ def get_array_filename(self, var, basedir='results'):
         that are not case sensitive (e.g. on Windows).
         """
         varname = self.get_array_name(var, access_data=False)
-        return os.path.join(basedir, f"{varname}_{str(hash(varname))}")
+        return os.path.join(basedir, f"{varname}_{str(zlib.crc32(varname.encode('utf-8')))}")
 
     def add_array(self, var):
         # Note that a dynamic array variable is added to both the arrays and

brian2/monitors/spikemonitor.py

@@ -111,7 +111,7 @@ def __init__(self, source, event, variables=None, record=True,
         # Some dummy code so that code generation takes care of the indexing
         # and subexpressions
         code = [f'_to_record_{v} = _source_{v}'
-                for v in self.record_variables]
+                for v in sorted(self.record_variables)]
         code = '\n'.join(code)
 
         self.codeobj_class = codeobj_class