Changeset 2508 for inundation/utilities/numerical_tools.py

Timestamp:

Mar 9, 2006, 12:25:31 PM (19 years ago)

Author:

ole

Message:

First step towards moving util_ext.h out from pyvolution as per ticket:31

File:

• inundation/utilities/numerical_tools.py (modified) (1 diff)

inundation/utilities/numerical_tools.py

@@ -124 +124 @@
 
 
+####################################################################
+#Python versions of function that are also implemented in numerical_tools_ext.c
+#
+
+def gradient_python(x0, y0, x1, y1, x2, y2, q0, q1, q2):
+    """
+    """
+
+    det = (y2-y0)*(x1-x0) - (y1-y0)*(x2-x0)
+    a = (y2-y0)*(q1-q0) - (y1-y0)*(q2-q0)
+    a /= det
+
+    b = (x1-x0)*(q2-q0) - (x2-x0)*(q1-q0)
+    b /= det
+
+    return a, b
+
+
+def gradient2_python(x0, y0, x1, y1, q0, q1):
+    """Compute radient based on two points and enforce zero gradient
+    in the direction orthogonal to (x1-x0), (y1-y0) 
+    """
+
+    #Old code
+    #det = x0*y1 - x1*y0
+    #if det != 0.0:
+    #    a = (y1*q0 - y0*q1)/det
+    #    b = (x0*q1 - x1*q0)/det
+
+    #Correct code (ON)
+    det = (x1-x0)**2 + (y1-y0)**2
+    if det != 0.0:
+        a = (x1-x0)*(q1-q0)/det
+        b = (y1-y0)*(q1-q0)/det
+        
+    return a, b        
+
+
+##############################################
+#Initialise module
+
+from utilities import compile
+if compile.can_use_C_extension('util_ext.c'):
+    from util_ext import gradient, gradient2#, point_on_line
+else:
+    gradient = gradient_python
+    gradient2 = gradient2_python    
+
+
+if __name__ == "__main__":
+    pass
+