SplitInformation.Splits()

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: TreeTools
 Title: Create, Modify and Analyse Phylogenetic Trees
-Version: 2.1.0
+Version: 2.1.0.9000
 Authors@R: c(
   person("Martin R.", 'Smith', role = c("aut", "cre", "cph"), 
          email = "martin.smith@durham.ac.uk",

NAMESPACE

@@ -151,6 +151,9 @@ S3method(SortTree,phylo)
 S3method(SplitImbalance,"NULL")
 S3method(SplitImbalance,Splits)
 S3method(SplitImbalance,phylo)
+S3method(SplitInformation,Splits)
+S3method(SplitInformation,numeric)
+S3method(SplitInformation,phylo)
 S3method(SplitsInBinaryTree,"NULL")
 S3method(SplitsInBinaryTree,Splits)
 S3method(SplitsInBinaryTree,default)

NEWS.md

@@ -1,3 +1,8 @@
+# TreeTools 2.1.0.9000 (2026-02-16) #
+
+- Add Splits and phylo methods for `SplitInformation()`
+
+
 # TreeTools 2.1.0 (2026-02-10) #
 
 - Add method `RenumberTips.Splits()`.
@@ -12,6 +17,7 @@
 - `MatrixToPhyDat()` gains `tipLabels` parameter.
 - Document return value for `J1Index()`.
 
+
 # TreeTools 2.0.0 (2025-09-23) #
 
 ## New functionality

R/Information.R

@@ -170,9 +170,29 @@ CharacterInformation <- function(tokens) {
 #' @template MRS
 #' @export
 SplitInformation <- function(A, B = A[1]) {
+  UseMethod("SplitInformation")
+}
+
+#' @rdname SplitInformation
+#' @export
+SplitInformation.numeric <- function(A, B = A[1]) {
   -(Log2TreesMatchingSplit(A, B) - Log2Unrooted.int(A + B))
 }
 
+#' @rdname SplitInformation
+#' @export
+SplitInformation.Splits <- function(A, B) {
+  nTip <- NTip(A)
+  tis <- TipsInSplits(A)
+  Log2Unrooted.int(nTip) - Log2Rooted.int(tis) - Log2Rooted.int(nTip - tis)
+}
+
+#' @rdname SplitInformation
+#' @export
+SplitInformation.phylo <- function(A, B) {
+  SplitInformation(as.Splits(A))
+}
+
 #' @rdname SplitInformation
 #' @param partitionSizes Integer vector specifying the number of taxa in each
 #' partition of a multi-partition split.

tests/testthat/test-information.R

@@ -12,6 +12,14 @@ test_that("Trees matching splits calculated correctly", {
   expect_equal(log(315/10395)/-log(2), SplitInformation(3, 5))
 })
 
+test_that("SplitInformation() handles Splits", {
+  t6 <- BalancedTree(6)
+  expect_equal(SplitInformation(t6), SplitInformation(as.Splits(t6)))
+  expect_equal(SplitInformation(t6), c(`8` = SplitInformation(3, 3),
+                                       `9` = SplitInformation(2, 4),
+                                       `11` = SplitInformation(4, 2)))
+})
+
 test_that("UnrootedTreesMatchingSplit() correct", {
   expect_equal(NRooted(3) * NRooted(5), UnrootedTreesMatchingSplit(c(3, 5)))
   expect_equal(LnRooted(30) + LnRooted(50), LnUnrootedTreesMatchingSplit(30, 50))