Something simple with formatting axes

If I was needing to plot a two dimensional graph. The horizontal axis is a positively oriented from 0 to infinity, but the vertical axis is oriented from 0 to negative infinity. The axes converge at zero. What I can't figure out is how to reverse just the vertical axis to have increasing negative values as the x axis increases.

Answer 1

[Walter Roberson]

set(gca, 'Ydir', 'reverse')

The vertical axes is the Y axes, and I followed your horizontal/vertical question, not your request to have increasing negative values as the x axis increases.