Merge pull request #20 from opesci/memory_align

navjotk · navjotk · commit 7022239931f0 · 2016-05-23T17:59:26.000+01:00
Force alignment of arrays in memory
diff --git a/devito/interfaces.py b/devito/interfaces.py
@@ -1,5 +1,6 @@
 import numpy as np
 from sympy import IndexedBase
+from tools import aligned
 
 
 class DenseData(IndexedBase):
@@ -19,7 +20,7 @@ def set_initializer(self, lambda_initializer):
         self.initializer = lambda_initializer
 
     def _allocate_memory(self):
-        self.pointer = np.zeros(self.var_shape, self.dtype, order='C')
+        self.pointer = aligned(np.zeros(self.var_shape, self.dtype, order='C'), alignment=64)
 
     @property
     def data(self):
diff --git a/devito/tools.py b/devito/tools.py
@@ -0,0 +1,14 @@
+import numpy as np
+
+
+def aligned(a, alignment=16):
+    if (a.ctypes.data % alignment) == 0:
+        return a
+
+    extra = alignment / a.itemsize
+    buf = np.empty(a.size + extra, dtype=a.dtype)
+    ofs = (-buf.ctypes.data % alignment) / a.itemsize
+    aa = buf[ofs:ofs+a.size].reshape(a.shape)
+    np.copyto(aa, a)
+    assert (aa.ctypes.data % alignment) == 0
+    return aa
