This is exactly the sort of thing that I thought a transform approach would make easier to do. So if it isn't urgent, waiting probably would be better. (by the way, we see exactly the same sort of log scale you propose in one of our older (non-python) packages. So there is a call for this sort of thing.
Perry On Jul 17, 2007, at 10:36 AM, Paul Kienzle wrote: > On Tue, Jul 17, 2007 at 08:33:47AM -0500, John Hunter wrote: >> Speaking of branches, we may need to seriously consider a branch >> here, >> mpl1. The changes here may involve breaking a fair amount of code, >> which I don't mind doing to get it right, but I'm somewhat >> inclined to >> branch off here for matplotlib1.0, with the goal of using traits, >> fixing axis handling (eg multiple y-axis with arbitrary placement), >> and rewriting the transforms. > > On the topic of transforms, I would like to be able to do dynamic > range > compression on a decaying oscillatory signal. Think of it as a > logarithmic > axis which supports negative numbers. AFAICT, the current transform > infrastructure does not allow me to add this as a third party package. > > The axis would look something like: > > |- 10**2 > | > |- 10**1 > | > |- 10**0 > | > |- 10**-1 > | > |- 0 > | > |- -10**-1 > | > |- -10**0 > > As well as a max and min parameter, there would have to be a cutoff > parameter. For auto axes, choose a cutoff which allows a reasonable > number of decades to be displayed (I'm guessing reasonable is seven). > > The transform would be something like the following: > > if (x[i] > cut) newx[i] = log10(x[i]) - log10cut; > else if (x[i] < -cut) newx[i] = log10cut - log10(-x[i]); > else newx[i] = 0.; > > with inverse: > > if (x[i] < 0) newx[i] = -pow(10.0, log10cut - x[i]); > else if (x[i] > 0) newx[i] = pow(10.0, x[i] - log10cut); > else x[i] = 0. > > Even extending the current LOG10 support would present a challenge of > how to get the cut value into the transform. > > Suggestions how I can implement this in the current architecture, or > should I wait for the new transforms code? > > - Paul > > > ---------------------------------------------------------------------- > --- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > Matplotlib-devel mailing list > Matplotlib-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-devel ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
