From d7264228c3c80a69a3a480d43079c1c369f71bf0 Mon Sep 17 00:00:00 2001
From: Walmes Zeviani <walmes@ufpr.br>
Date: Wed, 17 Oct 2018 18:59:50 -0300
Subject: [PATCH] =?UTF-8?q?Adiciona=20script=20com=20dicas=20para=20estudo?=
=?UTF-8?q?s=20de=20simula=C3=A7=C3=A3o.?=
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---
scripts/ce089-09.R | 71 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 71 insertions(+)
create mode 100644 scripts/ce089-09.R
diff --git a/scripts/ce089-09.R b/scripts/ce089-09.R
new file mode 100644
index 0000000..6e680d5
--- /dev/null
+++ b/scripts/ce089-09.R
@@ -0,0 +1,71 @@
+#=======================================================================
+# Formas eficientes para fazer estudos de simulação/reamostragem.
+
+#-----------------------------------------------------------------------
+# Cria a função com lista de todos os argumentos e use mapply().
+
+library(microbenchmark)
+
+# Curva de poder.
+power_k_groups <- function(k = 3,
+ r = 4,
+ sigma_group = 0.01,
+ simulations = 50,
+ alpha = 0.05) {
+ trt <- gl(n = k, k = r)
+ X <- model.matrix(~0 + trt)
+ results <- replicate(simulations, {
+ b <- rnorm(k, mean = 0, sigma_group)
+ y <- rnorm(k * r, mean = X %*% b, sd = 1)
+ anova(lm(y ~ X))[1, 5]
+ })
+ mean(results <= alpha)
+}
+
+# Criar o grid de condições (prototipar com um grid pequeno).
+grid <- expand.grid(k = 3:5,
+ r = c(3, 5, 8),
+ sigma_group = seq(0.01, 0.5, length.out = 10),
+ KEEP.OUT.ATTRS = FALSE)
+nrow(grid)
+
+# Aplicar.
+grid$taxa <- mapply(FUN = power_k_groups,
+ k = grid$k,
+ r = grid$r,
+ sigma_group = grid$sigma_group,
+ MoreArgs = list(simulations = 10,
+ alpha = 0.05),
+ SIMPLIFY = TRUE)
+
+#-----------------------------------------------------------------------
+# Usando purrr.
+
+library(purrr)
+
+grid$taxa <- pmap_dbl(.l = grid,
+ .f = power_k_groups,
+ simulations = 10,
+ alpha = 0.05)
+
+#-----------------------------------------------------------------------
+
+library(microbenchmark)
+
+microbenchmark(
+ mapply = {
+ mapply(FUN = power_k_groups,
+ k = grid$k,
+ r = grid$r,
+ sigma_group = grid$sigma_group,
+ MoreArgs = list(simulations = 10,
+ alpha = 0.05),
+ SIMPLIFY = TRUE)
+ },
+ pmap = {
+ pmap_dbl(.l = grid,
+ .f = power_k_groups,
+ simulations = 10,
+ alpha = 0.05)
+ },
+ replications = 20)
--
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