Use row number in parameter table to identify parameters

[sfcheung]

Note

This approach is more reliable than matching parameter specifications. This will also make it easier to support multiple-group models.

Status

Working on this branch: parameterid.

To-Do

• [x] Revise functions that compute stats for parameters to use parameter table row numbers.
  • [x] est_change()
  • [x] est_change_raw()
  • [x] est_change_approx()
  • [x] est_change_raw_approx()
• [x] Factor out the part to get est changes, and add wrappers to handle extraction of parameters.
• [x] Write a function to convert the ids generated above to lhs, op, rhs, and group columns. <- pars_id_to_lorg()
• [x] Write a function to convert lavaan syntax to positions in the parameter vector (output of coef() or parameterTable()). No need for the output of parameterEstimates() because the rows included are not fixed but depends on some arguments.
• [x] Write a function to convert positions back to parameter specifications (e.g., "x ~ y") <- May not be necessary because they are just names in the output of coef(). <- Not necessary. Can use lavaan::lav_partable_labels().

[sfcheung]

Done at e5ed94e9a5334980c482476f14908b55f8a984aa