[Scipy-svn] r5093 - in trunk/scipy/interpolate: . tests

[scipy-svn at scipy.org]

Author: ptvirtan
Date: 2008-11-13 15:20:50 -0600 (Thu, 13 Nov 2008)
New Revision: 5093

Modified:
   trunk/scipy/interpolate/fitpack2.py
   trunk/scipy/interpolate/tests/test_fitpack.py
Log:
interpolate: don't change the __class__ of a live UnivariateSpline object, if the object is an instance of user-defined subclass. (Fixes #660)

Modified: trunk/scipy/interpolate/fitpack2.py
===================================================================
--- trunk/scipy/interpolate/fitpack2.py	2008-11-13 21:03:45 UTC (rev 5092)
+++ trunk/scipy/interpolate/fitpack2.py	2008-11-13 21:20:50 UTC (rev 5093)
@@ -103,19 +103,28 @@
             pass
         elif ier==-1:
             # the spline returned is an interpolating spline
-            self.__class__ = InterpolatedUnivariateSpline
+            self._set_class(InterpolatedUnivariateSpline)
         elif ier==-2:
             # the spline returned is the weighted least-squares
             # polynomial of degree k. In this extreme case fp gives
             # the upper bound fp0 for the smoothing factor s.
-            self.__class__ = LSQUnivariateSpline
+            self._set_class(LSQUnivariateSpline)
         else:
             # error
             if ier==1:
-                self.__class__ = LSQUnivariateSpline
+                self._set_class(LSQUnivariateSpline)
             message = _curfit_messages.get(ier,'ier=%s' % (ier))
             warnings.warn(message)
 
+    def _set_class(self, cls):
+        self._spline_class = cls
+        if self.__class__ in (UnivariateSpline, InterpolatedUnivariateSpline,
+                              LSQUnivariateSpline):
+            self.__class__ = cls
+        else:
+            # It's an unknown subclass -- don't change class. cf. #660
+            pass
+
     def _reset_nest(self, data, nest=None):
         n = data[10]
         if nest is None:

Modified: trunk/scipy/interpolate/tests/test_fitpack.py
===================================================================
--- trunk/scipy/interpolate/tests/test_fitpack.py	2008-11-13 21:03:45 UTC (rev 5092)
+++ trunk/scipy/interpolate/tests/test_fitpack.py	2008-11-13 21:20:50 UTC (rev 5093)
@@ -36,6 +36,15 @@
         assert_almost_equal(lut.get_residual(),0.0)
         assert_array_almost_equal(lut([1,1.5,2]),[0,1,2])
 
+    def test_subclassing(self):
+        
+        class ZeroSpline(UnivariateSpline):
+            def __call__(self, x):
+                return 0*array(x)
+        
+        sp = ZeroSpline([1,2,3,4,5], [3,2,3,2,3], k=2)
+        assert_array_equal(sp([1.5, 2.5]), [0., 0.])
+
 class TestLSQBivariateSpline(TestCase):
     def test_linear_constant(self):
         x = [1,1,1,2,2,2,3,3,3]