fix ParameterScale sampler fixes #491 (#492)

* fix ParameterScaleUniform

* trafo in get_priors_from_df

* clarify documentation

Author: jvanhoefer

doc/documentation_data_format.rst

@@ -537,6 +537,9 @@ Detailed field description
 
   Prior parameters used for sampling of initial points for optimization,
   separated by a semicolon. Defaults to ``lowerBound;upperBound``.
+  The parameters are expected to be in linear scale except for the
+  ``parameterScale`` priors, where the prior parameters are expected to be
+  in parameter scale.
 
   So far, only numeric values will be supported, no parameter names.
   Parameters for the different prior types are:

petab/parameters.py

@@ -343,7 +343,8 @@ def get_priors_from_df(parameter_df: pd.DataFrame,
         # if no prior is specified, we assume a non-informative (uniform) one
         if prior_type == 'nan':
             prior_type = PARAMETER_SCALE_UNIFORM
-            prior_pars = (row[LOWER_BOUND], row[UPPER_BOUND])
+            prior_pars = (scale(row[LOWER_BOUND], par_scale),
+                          scale(row[UPPER_BOUND], par_scale))
 
         prior_list.append((prior_type, prior_pars, par_scale, par_bounds))