Creating the `vars_to_starts` as a dictionnary mapping variable to int is expensive in the case where we have a lot of variables. Instead it could map a variable group to an array (in the case of a `NDVariableArray`) or a list (for a `VariableDict`)
Creating the
vars_to_startsas a dictionnary mapping variable to int is expensive in the case where we have a lot of variables.Instead it could map a variable group to an array (in the case of a
NDVariableArray) or a list (for aVariableDict)