From 985f6a0f143fc829e8cb68d44fc7cb1e31cd6c97 Mon Sep 17 00:00:00 2001
From: Dmitry Shemetov <dshemetov@ucdavis.edu>
Date: Wed, 4 Sep 2024 13:57:13 -0700
Subject: [PATCH 1/2] feat: expose "method" arg of quantile_reg

---
 R/make_quantile_reg.R | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/R/make_quantile_reg.R b/R/make_quantile_reg.R
index 832ef50f8..f025bf6d6 100644
--- a/R/make_quantile_reg.R
+++ b/R/make_quantile_reg.R
@@ -22,7 +22,7 @@
 #' rq_spec <- quantile_reg(quantile_levels = c(.2, .8)) %>% set_engine("rq")
 #' ff <- rq_spec %>% fit(y ~ ., data = tib)
 #' predict(ff, new_data = tib)
-quantile_reg <- function(mode = "regression", engine = "rq", quantile_levels = 0.5) {
+quantile_reg <- function(mode = "regression", engine = "rq", quantile_levels = 0.5, method = "br") {
   # Check for correct mode
   if (mode != "regression") {
     cli_abort("`mode` must be 'regression'")
@@ -35,7 +35,7 @@ quantile_reg <- function(mode = "regression", engine = "rq", quantile_levels = 0
     cli::cli_warn("Sorting `quantile_levels` to increasing order.")
     quantile_levels <- sort(quantile_levels)
   }
-  args <- list(quantile_levels = rlang::enquo(quantile_levels))
+  args <- list(quantile_levels = rlang::enquo(quantile_levels), method = rlang::enquo(method))
 
   # Save some empty slots for future parts of the specification
   parsnip::new_model_spec(
@@ -54,9 +54,6 @@ make_quantile_reg <- function() {
     parsnip::set_new_model("quantile_reg")
   }
   parsnip::set_model_mode("quantile_reg", "regression")
-
-
-
   parsnip::set_model_engine("quantile_reg", "regression", eng = "rq")
   parsnip::set_dependency("quantile_reg", eng = "rq", pkg = "quantreg")
 
@@ -68,6 +65,14 @@ make_quantile_reg <- function() {
     func = list(pkg = "quantreg", fun = "rq"),
     has_submodel = FALSE
   )
+  parsnip::set_model_arg(
+    model = "quantile_reg",
+    eng = "rq",
+    parsnip = "method",
+    original = "method",
+    func = list(pkg = "quantreg", fun = "rq"),
+    has_submodel = FALSE
+  )
 
   parsnip::set_fit(
     model = "quantile_reg",
@@ -78,7 +83,6 @@ make_quantile_reg <- function() {
       protect = c("formula", "data", "weights"),
       func = c(pkg = "quantreg", fun = "rq"),
       defaults = list(
-        method = "br",
         na.action = rlang::expr(stats::na.omit),
         model = FALSE
       )
@@ -101,7 +105,6 @@ make_quantile_reg <- function() {
     object <- parsnip::extract_fit_engine(object)
     type <- class(object)[1]
 
-
     # can't make a method because object is second
     out <- switch(type,
       rq = dist_quantiles(unname(as.list(x)), object$quantile_levels), # one quantile
@@ -117,7 +120,6 @@ make_quantile_reg <- function() {
     return(data.frame(.pred = out))
   }
 
-
   parsnip::set_pred(
     model = "quantile_reg",
     eng = "rq",

From 1040633b2569c6eecf646f39cf9a6e6e528629f6 Mon Sep 17 00:00:00 2001
From: Dmitry Shemetov <dshemetov@ucdavis.edu>
Date: Wed, 4 Sep 2024 15:41:10 -0700
Subject: [PATCH 2/2] doc: document

---
 R/make_quantile_reg.R |  2 ++
 man/quantile_reg.Rd   | 10 +++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/R/make_quantile_reg.R b/R/make_quantile_reg.R
index f025bf6d6..4cca17847 100644
--- a/R/make_quantile_reg.R
+++ b/R/make_quantile_reg.R
@@ -11,6 +11,8 @@
 #'   "rq" is supported.
 #' @param quantile_levels A scalar or vector of values in (0, 1) to determine which
 #'   quantiles to estimate (default is 0.5).
+#' @param method A fitting method used by [quantreg::rq()]. See the
+#'   documentation for a list of options.
 #'
 #' @export
 #'
diff --git a/man/quantile_reg.Rd b/man/quantile_reg.Rd
index 8e576ac84..2101c5a0e 100644
--- a/man/quantile_reg.Rd
+++ b/man/quantile_reg.Rd
@@ -4,7 +4,12 @@
 \alias{quantile_reg}
 \title{Quantile regression}
 \usage{
-quantile_reg(mode = "regression", engine = "rq", quantile_levels = 0.5)
+quantile_reg(
+  mode = "regression",
+  engine = "rq",
+  quantile_levels = 0.5,
+  method = "br"
+)
 }
 \arguments{
 \item{mode}{A single character string for the type of model.
@@ -15,6 +20,9 @@ The only possible value for this model is "regression".}
 
 \item{quantile_levels}{A scalar or vector of values in (0, 1) to determine which
 quantiles to estimate (default is 0.5).}
+
+\item{method}{A fitting method used by \code{\link[quantreg:rq]{quantreg::rq()}}. See the
+documentation for a list of options.}
 }
 \description{
 \code{quantile_reg()} generates a quantile regression model \emph{specification} for