update docs and failing test

R/args.R

@@ -1268,23 +1268,29 @@ process_init_approx <- function(init, num_procs, model_variables = NULL,
   # Calculate unique draws based on 'lw' using base R functions
   unique_draws = length(unique(draws_df$lw))
   if (num_procs > unique_draws) {
-    if (inherits(init, "CmdStanPathfinder")) {
-      stop(paste0("Not enough distinct draws (", num_procs, ") in pathfinder fit to create inits. Try running Pathfinder with psis_resample=FALSE"))
+    if (inherits(init, " CmdStanPathfinder ")) {
+      algo_name = " Pathfinder "
+      extra_msg = " Try running Pathfinder with psis_resample=FALSE."
+    } else if (inherits(init, "CmdStanVB")) {
+      algo_name = " CmdStanVB "
+      extra_msg = ""
+    } else if (inherits(init, " CmdStanLaplace ")) {
+      algo_name = " CmdStanLaplace "
+      extra_msg = ""
     } else {
-      stop(paste0("Not enough distinct draws (", num_procs, ") to create inits."))
+      algo_name = ""
+      extra_msg = ""
     }
+    stop(paste0("Not enough distinct draws (", num_procs, ") in", algo_name ,
+      "fit to create inits.", extra_msg))
   }
   if (unique_draws < (0.95 * nrow(draws_df))) {
     temp_df = stats::aggregate(.draw ~ lw, data = draws_df, FUN = min)
     draws_df = posterior::as_draws_df(merge(temp_df, draws_df, by = 'lw'))
     draws_df$weight = exp(draws_df$lw - max(draws_df$lw))
   } else {
-    if (inherits(init, "CmdStanPathfinder") && (init$metadata()$psis_resample || !init$metadata()$calculate_lp)) {
-        draws_df$weight = rep(1.0, nrow(draws_df))
-    } else {
       draws_df$weight = posterior::pareto_smooth(
         exp(draws_df$lw - max(draws_df$lw)), tail = "right", return_k=FALSE)
-    }
   }
   init_draws_df = posterior::resample_draws(draws_df, ndraws = num_procs,
                                             weights = draws_df$weight, method = "simple_no_replace")
@@ -1308,7 +1314,22 @@ process_init_approx <- function(init, num_procs, model_variables = NULL,
 process_init.CmdStanPathfinder <- function(init, num_procs, model_variables = NULL,
                                            warn_partial = getOption("cmdstanr_warn_inits", TRUE),
                                            ...) {
-  process_init_approx(init, num_procs, model_variables, warn_partial)
+  if (!init$metadata()$calculate_lp) {
+    validate_fit_init(init, model_variables)
+    # Convert from data.table to data.frame
+    draws_df = init$draws(format = "df")
+    if (is.null(model_variables)) {
+      model_variables = list(parameters = colnames(draws_df)[3:(length(colnames(draws_df)) - 3)])
+    }
+    draws_df$weight = rep(1.0, nrow(draws_df))
+    init_draws_df = posterior::resample_draws(draws_df, ndraws = num_procs,
+      weights = draws_df$weight, method = "simple_no_replace")
+    init_draws_lst = process_init(init_draws_df,
+      num_procs = num_procs, model_variables = model_variables, warn_partial)
+    return(init_draws_lst)
+  } else {
+    process_init_approx(init, num_procs, model_variables, warn_partial)
+  }
 }
 
 #' Write initial values to files if provided as a `CmdStanVB` class

man-roxygen/model-common-args.R

@@ -44,19 +44,21 @@
 #'  has argument `chain_id` it will be supplied with the chain id (from 1 to
 #'  number of chains) when called to generate the initial values. See
 #'  **Examples**.
-#'  * A [`CmdStanMCMC`], [`CmdStanMLE`], [`CmdStanVB`], or [`CmdStanPathfinder`]
-#'  fit object. If the fit object's parameters are only a subset of the model
+#'  * A [`CmdStanMCMC`], [`CmdStanMLE`], [`CmdStanVB`], [`CmdStanPathfinder`],
+#'  or [`CmdStanLaplace`] fit object.
+#'  If the fit object's parameters are only a subset of the model
 #'  parameters then the other parameters will be drawn by Stan's default
 #'  initialization. The fit object must have at least some parameters that are the
-#'  same name and dimensions as the current Stan model. For the `sampling` and
-#'  `pathfinder` method, if the fit object has less samples than the requested
+#'  same name and dimensions as the current Stan model. For the `sample` and
+#'  `pathfinder` method, if the fit object has fewer draws than the requested
 #'  number of chains/paths then the inits will be drawn using sampling with
 #'  replacement. Otherwise sampling without replacement will be used.
 #'  When a [`CmdStanPathfinder`] fit object is used as the init, if
-#'  `psis_resample` was set to `FALSE` and `calculate_lp` was
-#'  set to `TRUE` (default), then PSIS resampling will be used as weights.
-#'  if `calculate_lp` is `FALSE` then sampling without replacement will be used
-#'  to select the draws.
+#'. `psis_resample` was set to `FALSE` and `calculate_lp` was
+#'  set to `TRUE` (default), then resampling without replacement with Pareto
+#'  smoothed weights will be used. If `psis_resample` was set to `TRUE` or
+#'  `calculate_lp` was set to `FALSE` then sampling without replacement with
+#'  uniform weights will be used to select the draws.
 #'  PSIS resampling is used to select the draws for  [`CmdStanVB`] fit objects.
 #'
 #'  * A type inheriting from `posterior::draws`. If the draws object has less