On Wednesday 15 August 2007 03:18:25 pm you wrote: > On Wed, Aug 15, 2007 at 09:57:21AM -0400, Darren Dale wrote: > > On Tuesday 14 August 2007 07:35:43 pm Darren Dale wrote: > > > I'm developing an application for work and need to plot some spectra on > > > a logscale. I can recreate my problem with embedding_in_qt4, by > > > replacing MyDynamicMplCanvas.compute_initial_figure with this: > > > > > > def compute_initial_figure(self): > > > self.axes.plot([0, 1, 2, 3], [1, 2, 0, 4], 'r') > > > self.axes.set_yscale('log') > > > > > > [...] > > > File > > > "/usr/lib64/python2.5/site-packages/matplotlib-0.90.1_r3709-py2.5-linux > > >-x86 _64.egg/matplotlib/axes.py", line 1664, in set_ylim > > > raise ValueError('Cannot set nonpositive limits with log > > > transform') ValueError: Cannot set nonpositive limits with log > > > transform > > > > > > I get that error even if I modify the update figure function so there > > > is no possibility of zeros occuring in the data > > > > I have tracked this back through axes.cla(), which is called when > > axes._hold is False, to axis.cla(). axis.cla() resets the locators, but > > the transforms are still set to mtrans.LOG10. Since plot is called by > > loglog, and semilog*, it shouldn't be using any methods that modify > > locators. If cla() resets the transforms, then the behavior of plot will > > be different, preserving log transforms when hold is True, but changing > > to linear transforms when hold is False. > > > > I wonder if cla() is trying to do too much. Maybe the initial setting of > > locators should be moved out of cla(), which is called by Axes.__init__, > > and into Axis.__init__. Then calls to cla() will preserve the scaling, > > and the behavior of plot() will be consistent, regardless of the whether > > hold is enabled or not. > > The other option is to do something sensible when axes limits are > negative on the log scale.
Thats a seperate, but important issue. In the case I described, the state of the plot becomes a mash of log transforms and linear locators. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel