PRF: only do expensive things once

tacaswell · tacaswell · commit 2d0cc7da4226 · 2015-07-28T03:19:19.000-04:00
Looking up MachAr was taking about 10ms which is way to slow to be
inside of the mouse motion event loop.

We are using it to get a constant so we can look it up and compute
the constant once at the top.
diff --git a/lib/matplotlib/transforms.py b/lib/matplotlib/transforms.py
@@ -50,7 +50,8 @@
 from .path import Path
 
 DEBUG = False
-
+# we need this later, but this is very expensive to set up
+MINFLOAT = np.MachAr(float).xmin
 MaskedArray = ma.MaskedArray
 
 
@@ -2738,7 +2739,7 @@ def nonsingular(vmin, vmax, expander=0.001, tiny=1e-15, increasing=True):
         swapped = True
 
     maxabsvalue = max(abs(vmin), abs(vmax))
-    if maxabsvalue < (1e6 / tiny) * np.MachAr(float).xmin:
+    if maxabsvalue < (1e6 / tiny) * MINFLOAT:
         vmin = -expander
         vmax = expander
 
