From f400a6cdf74278bd9d58a9e71d00be3ea25064be Mon Sep 17 00:00:00 2001
From: Walter <walterxie@users.noreply.github.com>
Date: Fri, 24 May 2024 11:24:29 +1200
Subject: [PATCH] add if to optional arg in Sample #478

---
 lphy-base/src/main/java/lphy/base/distribution/Sample.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lphy-base/src/main/java/lphy/base/distribution/Sample.java b/lphy-base/src/main/java/lphy/base/distribution/Sample.java
index 067fa3e7..6aa541f2 100644
--- a/lphy-base/src/main/java/lphy/base/distribution/Sample.java
+++ b/lphy-base/src/main/java/lphy/base/distribution/Sample.java
@@ -87,7 +87,7 @@ public Map<String, Value> getParams() {
         return new TreeMap<>() {{
             put(ParameterNames.ArrayParamName, x);
             put(ParameterNames.SizeParamName, size);
-            put(replParamName, replace);
+            if (replace != null) put(replParamName, replace); // optional
         }};
     }