Merge pull request #137 from markmfredrickson/issue-127

PR For Issue 127

R/Design.R

@@ -326,6 +326,12 @@ makeDesigns <- function(fmla, data) {
   data.data <- model.frame(data.fmla, data, na.action = na.pass) #
   data.data$'(weights)' <- data$'(weights)'
 
+  # Convert remaining character columns to factors so make behavior consistent (issue #127)
+  chrs <- colnames(data.data)[sapply(data.data, is.character)]
+  for (f in chrs) {
+    data.data[, f] <- as.factor(data.data[, f])
+  }
+
   # knock out any levels that are not used
   fcts <- colnames(data.data)[sapply(data.data, is.factor)]
   for (f in fcts) {

R/utils.R

@@ -370,8 +370,15 @@ slm.wfit.csr <- function(x, y, weights, ...) {
 ## @return matrix of \code{ncol(mat)} rows and col rank (mat) columns
 ## @author Ben Hansen
 ## @keywords internal
-XtX_pseudoinv_sqrt <- function(mat, mat.is.XtX = FALSE, tol = .Machine$double.eps^0.5) {
-  pst.svd <- try(svd(mat, nu = 0))
+XtX_pseudoinv_sqrt <- function(mat, mat.is.XtX = FALSE, tol = .Machine$double.eps^0.5)
+{
+
+  if (nrow(mat) == 0 && ncol(mat) == 0)
+  {
+    stop("Cannot calculate pseudoinverse: perhaps all covariates are constant (within strata)?")
+  }
+
+  pst.svd <- try(svd(mat, nu=0))
 
   if (inherits(pst.svd, "try-error")) {
     pst.svd <- propack.svd(mat)

tests/testthat/test.balanceTest.R

@@ -401,3 +401,42 @@ test_that("balanceTest agrees with other methods where appropriate", {
   expect_equivalent(bt2m$overall[1, "p.value"], summary(cr2)$sctest[["pvalue"]])
   })
 })
+
+test_that("Constant variables", {
+
+  set.seed(393911)
+  d <- data.frame(xc = rep(1, 100),
+                  xv = runif(n = 100),
+                  s = as.factor(sample(letters[1:3], 100, replace = TRUE)),
+                  z = rep(c(1,0), 50))
+
+  ## this should be ok, no error
+  bt <- balanceTest(z ~ xv + xc, data = d)
+
+  ## but this gives problems
+  expect_error(balanceTest(z ~ xc, data = d),
+               "Cannot calculate pseudoinverse")
+
+  ## this too
+  expect_error(balanceTest(z ~ s + strata(s), data = d),
+               "Cannot calculate pseudoinverse")
+})
+
+
+test_that("Characters and factors", {
+
+  ## generally we expect characters and factors to behave the same.
+
+  set.seed(393911)
+  tmp <- sample(letters[1:3], 100, replace = TRUE)
+  d <- data.frame(char = tmp,
+                  fact = as.factor(tmp),
+                  z = rep(c(1,0), 50),
+                  stringsAsFactors = FALSE)
+
+  btc <- balanceTest(z ~ char, data = d)
+  btf <- balanceTest(z ~ fact, data = d)
+
+  expect_equal(dim(btc$results), dim(btf$results))
+  expect_equal(btc$overall, btf$overall)
+})