Adjusting y-axis scale in PyPlot

Question

I have a PyPlot script that shows multiple plots. One of the plots (gpu) I wanted to scale down so I will see it in the lower part of the graph (as in the picture). In order to achieve this I set the axis ylim to 300.

if ymax is not None:
    ax.set_ylim(ax.get_ylim()[0], ymax)

The problem is that it messed up to lower ylim, and it is no longer in line with the rest of the axes. Any idea how I can fix that? Thanks.

Answer 1

This is because matplotlib by default adds a 5% margin to the data limits on the axes (since the style changes in matplotlib v2.0 ).

Let's say your data limits were 0 – 100 , matplotlib would have added 5% on the top and bottom, so the axis limits would have been -5 – 105 .

In your case, you have changed the upper limit to 300 , but not modified the lower margin.

So, you probably want to set the limits to -15 – 315 , to be consistent with the others twin axes.

Note: Of course this relies on you using the default for ax.margins . If you have modified that (eg by setting ax.margins or using the rcParam axes.ymargin ), you need to modify the answer above with the relevant margin.