pyrtid.utils.random_field.get_normalized_std_from_lognormal_params#

pyrtid.utils.random_field.get_normalized_std_from_lognormal_params(mean: float, std: float) → float[source]#

Get the standard deviation of the normalized log-normal distribution.

Let $X$ be log-normally distributed. Denote $mu_{X}$ and $sigma_{X}$ as the mean and standard deviation of $X$. The standard deviation $sigma$ of $log{X}$ is given by:

\[\sigma = \sqrt{\ln \left(1+{\frac {\sigma _{X}^{2}}{\mu _{X}^{2}}}\right)}\]

See: https://en.wikipedia.org/wiki/Log-normal_distribution#Generation_and_parameters

Parameters

  • mean (float) – The mean of the log-normal distribution.

  • std (float) – The standard deviation of the log-normal distribution.

Returns

The standard deviation of the normalized distribution.

Return type

float