Addresses a slient computation hiccup with + log(phat[k] / phat[K]) (…

…#5)
coatless-rpkg · Oct 29, 2020 · e59e48e · e59e48e
1 parent e625257
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diff --git a/DESCRIPTION b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: msos
 Type: Package
 Title: Data Sets and Functions Used in Multivariate Statistics: Old School by John Marden
-Version: 1.1.1
+Version: 1.1.2
 Authors@R: c(
              person("John", "Marden", role = c("aut", "cph"),
                     email = "jimarden@illinois.edu"),

diff --git a/NEWS.md b/NEWS.md
@@ -1,3 +1,9 @@
+# msos 1.1.2 - Hotfix - "Old School Unbalanced"
+
+## CHANGES
+
+- Fixed `lda()`'s computation for unbalanced data sets. (thanks [Trevor Park](https://stat.illinois.edu/directory/profile/thp2))
+
 # msos 1.1.1 - Hotfix - "Old School Revitalized"
 
 ## CHANGES

diff --git a/R/lda.R b/R/lda.R
@@ -48,8 +48,7 @@ lda <-
     ak <- NULL
     vi <- solve(v)
     for (k in 1:K) {
-      c0 <- -(1 / 2) * (m[k, ] %*% vi %*% m[k, ] - m[K, ] %*% vi %*% m[K, ])
-      +log(phat[k] / phat[K])
+      c0 <- -(1 / 2) * (m[k, ] %*% vi %*% m[k, ] - m[K, ] %*% vi %*% m[K, ]) + log(phat[k] / phat[K])
       ck <- c(ck, c0)
       a0 <- vi %*% (m[k, ] - m[K, ])
       ak <- cbind(ak, a0)