Changeset 4249

Timestamp:

Feb 9, 2007, 3:26:03 PM (18 years ago)

Author:

ole

Message:

Made get_machine_precision() fast by using precomputed, global variable.

File:

• anuga_core/source/anuga/utilities/numerical_tools.py (modified) (2 diffs)

anuga_core/source/anuga/utilities/numerical_tools.py

@@ -26 +26 @@
 # Note, INF is used instead of NAN (Not a number), since Numeric has no NAN
 # if we use a package that has NAN, this should be updated to use NAN.
+
+# Static variable used by get_machine_precision
+machine_precision = None
 
 
@@ -303 +306 @@
 def get_machine_precision():
     """Calculate the machine precision for Floats
-    """
-
-    epsilon = 1.
-    while epsilon/2 + 1. > 1.:
-        epsilon /= 2
-
-    return epsilon    
+
+    Depends on static variable machine_precision in this module
+    as this would otherwise require too much computation.
+    """
+
+    global machine_precision
+    
+    if machine_precision is None:
+        epsilon = 1.
+        while epsilon/2 + 1. > 1.:
+            epsilon /= 2
+
+        machine_precision = epsilon
+
+    return machine_precision    
 
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