Merge pull request #218 from prabhuramachandran/add_gpu_pull_for_equa…

…tions

Fix subtle issue with automatic syncing on gpu.

pysph/sph/acceleration_eval_gpu_helper.py

@@ -239,7 +239,6 @@ def _sync_from_gpu(self, eq):
 
     def _converged(self, equations):
         for eq in equations:
-            self._sync_from_gpu(eq)
             if not (eq.converged() > 0):
                 return False
         return True

pysph/sph/equation.py

@@ -418,6 +418,21 @@ def converged(self):
         """
         return 1.0
 
+    def _pull(self, *args):
+        """Pull attributes from the GPU if needed.
+
+        The GPU reduce and converged methods run on the host and not on
+        the device and this is useful to call there.  This is not useful
+        on the CPU as this does not matter which is why this is a
+        private method.
+        """
+        if hasattr(self, '_gpu'):
+            ary = self._gpu.get()
+            if len(args) == 0:
+                args = ary.dtype.names
+            for arg in args:
+                setattr(self, arg, ary[arg][0])
+
 
 ###############################################################################
 # `Group` class.
@@ -878,7 +893,7 @@ def get_equation_wrappers(self, known_types={}):
             modified_classes = self._update_for_local_memory(predefined, eqs)
 
         code_gen = self._Converter_Class(known_types=predefined)
-        ignore = ['reduce']
+        ignore = ['reduce', 'converged']
         for cls in sorted(classes.keys()):
             src = code_gen.parse_instance(eqs[cls], ignore_methods=ignore)
             wrappers.append(src)

pysph/sph/tests/test_acceleration_eval.py

@@ -721,6 +721,9 @@ def post_loop(self, d_idx, d_au):
                     self.conv = 1
 
             def converged(self):
+                if hasattr(self, '_pull'):
+                    # _pull is not available on CPU.
+                    self._pull('conv')
                 return self.conv
 
         equations = [Group(