inst/tests/rms2.r

In rms: Regression Modeling Strategies

## From Jerome Asselin  https://github.com/harrelfe/rms/issues/32
require(rms)
df <- data.frame(y=rnorm(21), day=weekdays(Sys.Date()-(1:21), abbr=TRUE))
df$day.ordered <-
  with(df, factor(as.character(day),
                  levels=c("Sun","Mon","Tue","Wed","Thu","Fri","Sat"),
                  ordered=TRUE))
options(contrasts=c("contr.treatment", "contr.treatment"))
fit1 <- ols(y ~ day, data=df)
fit2 <- ols(y ~ day.ordered, data=df)
df.char <- df
df.char$day.ordered <- as.character(df.char$day.ordered)
w <- cbind(orig          = predict(fit1),
      orig.newdata       = predict(fit1, newdata=df),
      ordered            = predict(fit2),
      ordered.newdata    = predict(fit2, newdata=df),
      ordered.workaround = predict(fit2, newdata=df.char))
round(w[, -1] - w[, 1], 3)

# From oscar0936330161@gmail.com Oscar Chang
set.seed(8787)
n <- 1000
x1 <- factor(sample(c(0, 1), n, replace = T), ordered=TRUE)
y  <- sample(c(1, 2, 3, 4), n, replace = T)
w <- try(orm(y ~ x1), silent=TRUE)
w
x1 <- factor(sample(c(0, 1), n, replace = T))
orm(y ~ x1)