diff --git a/pytriqs/gf/local/matrix_stack.pyx b/pytriqs/gf/local/matrix_stack.pyx
index 9fcc95ee..76b54753 100644
--- a/pytriqs/gf/local/matrix_stack.pyx
+++ b/pytriqs/gf/local/matrix_stack.pyx
@@ -6,7 +6,7 @@ class MatrixStack:
         """
         """
         self.data = A
-        self.is_double = A.dtype in [numpy.float, numpy.float64, numpy.float128, numpy.float, numpy.float_]
+        self.is_double = A.dtype in [numpy.float, numpy.float32, numpy.float64, numpy.float_]
 
     def add(self, M):
         if self.is_double: