preserve attributes from mh sampler; test use of index

R/samplers.R

@@ -209,8 +209,8 @@
     b = model, ns = n * thin,
     burn = burnin, thin = thin, t.df = t_df, rw.scale = rw_scale
   ))
-  rw_acceptance <- betas[["rw.accept"]]
-  fixed_acceptance <- betas[["accept"]]
+  rw_acceptance <- attr(betas, "rw_acceptance")
+  fixed_acceptance <- attr(betas, "fixed_acceptance")
   betas <- betas[["bs"]]
   if (!is.null(index)) {
     betas <- betas[, index, drop = FALSE]
@@ -250,7 +250,13 @@
 
   # if index provided, subset the draws
   if (!is.null(index)) {
+    fx_a <- attr(draws, "fixed_acceptance")
+    rw_a <- attr(draws, "rw_acceptance")
     draws <- draws[, index, drop = FALSE]
+    if (!is.null(fx_a)) {
+      attr(draws, "fixed_acceptance") <- fx_a
+      attr(draws, "rw_acceptance") <- rw_a
+    }
   }
 
   # return the user-supplied draws

tests/testthat/test-samplers.R

@@ -60,6 +60,13 @@ test_that("generate_draws() works for a GAM with MH", {
   expect_true(is.matrix(drws1))
   expect_identical(dim(drws1), c(20L, 37L))
   expect_identical(drws1, drws2)
+
+  expect_silent(drws3 <- generate_draws(m_gam, n = 20, method = "mh",
+    burnin = 100, thin = 2, t_df = 4, rw_scale = 0.3, seed = 2, index = 2:10))
+  expect_type(drws3, "double")
+  expect_true(is.matrix(drws3))
+  expect_identical(dim(drws3), c(20L, 9L))
+  expect_identical(drws3, drws1[, 2:10])
 })
 
 test_that("generate_draws() fails for INLA", {
@@ -82,11 +89,25 @@ test_that("generate_draws() works for a GAM with mgcv mvn()", {
 test_that("user_draws() works for a GAM", {
   expect_silent(drws1 <- generate_draws(m_gam, n = 20, method = "gaussian",
     seed = 2))
+  expect_silent(drws2 <- generate_draws(m_gam, n = 20, method = "mh",
+    seed = 2))
   expect_silent(udrws <- user_draws(m_gam, draws = drws1))
   expect_type(udrws, "double")
   expect_true(is.matrix(udrws))
   expect_identical(dim(udrws), c(20L, 37L))
   expect_identical(udrws, drws1)
+
+  expect_silent(udrws <- user_draws(m_gam, draws = drws1, index = 2:10))
+  expect_type(udrws, "double")
+  expect_true(is.matrix(udrws))
+  expect_identical(dim(udrws), c(20L, 9L))
+  expect_identical(udrws, drws1[, 2:10])
+
+  expect_silent(udrws <- user_draws(m_gam, draws = drws2, index = 2:10))
+  expect_type(udrws, "double")
+  expect_true(is.matrix(udrws))
+  expect_identical(dim(udrws), c(20L, 9L))
+  expect_identical(udrws, drws2[, 2:10])
 })
 
 test_that("user_draws() fails for incorrect matrix of draws", {
@@ -96,4 +117,6 @@ test_that("user_draws() fails for incorrect matrix of draws", {
     "Supplied 'draws' doesn't match number of model coefficients.
 Number of model coefs: 37
 Number of columns in 'draws': 10")
+  expect_error(user_draws(m_gam, draws = 1:10),
+    "Supplied 'draws' is not a matrix of coefficients.")
 })