From 9a748f39699a38f480b10a44cf7510efc2e771da Mon Sep 17 00:00:00 2001
From: Hugo Gruson <Bisaloo@users.noreply.github.com>
Date: Mon, 6 Nov 2023 17:35:36 +0100
Subject: [PATCH] Sum loglikelihoods before exponentiating

---
 R/likelihood.R | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/R/likelihood.R b/R/likelihood.R
index 63b33af1..68f0f24c 100644
--- a/R/likelihood.R
+++ b/R/likelihood.R
@@ -134,17 +134,19 @@ likelihood <- function(chains, statistic = c("size", "length"), offspring_dist,
     likelihoods[sx[!(sx %in% exclude)]]
   })
 
-  ## transform log-likelihoods into likelihoods if required
-  if (isFALSE(log)) {
-    chains_likelihood <- lapply(chains_likelihood, exp)
+  ## if individual == FALSE, return the joint log-likelihood
+  ## (sum of the log-likelihoods)
+  if (!individual) {
+    chains_likelihood <- vapply(chains_likelihood, sum, 0)
   }
 
-  ## if individual == FALSE, return the joint log-likelihood
-  ## (sum of the log-likelihoods), if log == TRUE, else
-  ## multiply the likelihoods
-  if (isFALSE(individual)) {
-    summarise_func <- ifelse(log, sum, prod)
-    chains_likelihood <- vapply(chains_likelihood, summarise_func, 0)
+  ## transform log-likelihoods into likelihoods if required
+  if (!log) {
+    if (individual) {
+      chains_likelihood <- lapply(chains_likelihood, exp)
+    } else {
+      chains_likelihood <- exp(chains_likelihood)
+    }
   }
 
   return(chains_likelihood)