Faster real_if_close.

anntzer · anntzer · commit 9fba2cb5ebdd · 2016-03-30T19:10:26.000-07:00
Because of the complexity of `allclose`, `real_if_close(t)` used to be
~2.5-3x slower than, say, `t + t`.  This patch makes it approximately as
fast.
diff --git a/numpy/lib/type_check.py b/numpy/lib/type_check.py
@@ -424,7 +424,7 @@ def real_if_close(a,tol=100):
         from numpy.core import getlimits
         f = getlimits.finfo(a.dtype.type)
         tol = f.eps * tol
-    if _nx.allclose(a.imag, 0, atol=tol):
+    if _nx.all(_nx.absolute(a.imag) < tol):
         a = a.real
     return a
 
