Fixed bug in MaxNLocator by changing Locator.nonsingular().

efiring · efiring · commit 9d5b7160ca7f · 2006-03-16T08:30:23.000Z
svn path=/trunk/matplotlib/; revision=2149
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,10 +1,16 @@
-2006-03-14 Added import of compatibility library for newer numpy 
+2006-03-15 Fixed bug in MaxNLocator revealed by daigos@infinito.it.
+           The main change is that Locator.nonsingular now adjusts
+           vmin and vmax if they are nearly the same, not just if
+           they are equal.  A new kwarg, "tiny", sets the threshold. -
+           EF
+
+2006-03-14 Added import of compatibility library for newer numpy
            linear_algebra - TEO
 
 2006-03-12 Extended "load" function to support individual columns and
-	   moved "load" and "save" into matplotlib.mlab so they can be
-	   used outside of pylab -- see examples/load_converter.py -
-	   JDH
+           moved "load" and "save" into matplotlib.mlab so they can be
+           used outside of pylab -- see examples/load_converter.py -
+           JDH
 
 2006-03-12 Added AutoDateFormatter and AutoDateLocator submitted
            by James Evans. Try the load_converter.py example for a
@@ -13,11 +19,11 @@
 2006-03-11 Added subprocess module from python-2.4 - DSD
 
 2006-03-11 Fixed landscape orientation support with the usetex
-           option. The backend_ps print_figure method was 
+           option. The backend_ps print_figure method was
            getting complicated, I added a _print_figure_tex
            method to maintain some degree of sanity - DSD
 
-2006-03-11 Added "papertype" savefig kwarg for setting 
+2006-03-11 Added "papertype" savefig kwarg for setting
            postscript papersizes. papertype and ps.papersize
            rc setting can also be set to "auto" to autoscale
            pagesizes - DSD
@@ -29,7 +35,7 @@
 
 2006-03-07 Fixed bug in backend_ps related to C0-C6 papersizes,
            which were causing problems with postscript viewers.
-           Supported page sizes include letter, legal, ledger, 
+           Supported page sizes include letter, legal, ledger,
            A0-A10, and B0-B10 - DSD
 
 ===============================================================
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -518,10 +518,10 @@ def zoom(self, direction):
         step = 0.1*interval*direction
         self.viewInterval.set_bounds(vmin + step, vmax - step)
 
-    def nonsingular(self, vmin, vmax, expander = 0.001):
+    def nonsingular(self, vmin, vmax, expander=0.001, tiny=1e-6):
         if vmax < vmin:
             vmin, vmax = vmax, vmin
-        if vmin==vmax:
+        if vmax - vmin < max(abs(vmin), abs(vmax)) * tiny:
             if vmin==0.0:
                 vmin -= 1
                 vmax += 1
@@ -729,9 +729,10 @@ def autoscale(self):
 
 def scale_range(vmin, vmax, n = 1, threshold=100):
     dv = abs(vmax - vmin)
-    if dv == 0:
-        return 1.0, 0.0
     meanv = 0.5*(vmax+vmin)
+    var = dv/max(abs(vmin), abs(vmax))
+    if var < 1e-12:
+        return 1.0, 0.0
     if abs(meanv)/dv < threshold:
         offset = 0
     elif meanv > 0:
