class ExpScale(a=2.718281828459045, b=1, c=1, inverse=False, minpos=1e-300, **kwargs)[source]

Bases: proplot.axistools._ScaleBase, matplotlib.scale.ScaleBase

An “exponential scale”. When inverse is False (the default), this performs the transformation


where the constants \(a\), \(b\), and \(C\) are set by the input (see below). When inverse is True, this performs the inverse transformation

\[(\log_a(x) - \log_a(C))/b\]

which in appearence is equivalent to LogScale since it is just a linear transformation of the logarithm.

  • a (float, optional) – The base of the exponential, i.e. the \(a\) in \(Ca^{bx}\).

  • b (float, optional) – The scale for the exponent, i.e. the \(b\) in \(Ca^{bx}\).

  • c (float, optional) – The coefficient of the exponential, i.e. the \(C\) in \(Ca^{bx}\).

  • minpos (float, optional) – The minimum permissible value, used to truncate negative values.

  • inverse (bool, optional) – If True, the “forward” direction performs the inverse operation.

Attributes Summary


The registered scale name.

Methods Summary

limit_range_for_scale(vmin, vmax, minpos)

Returns the range vmin and vmax limited to positive numbers.