From 8d039b80618659a1b27f571f7b4190cb44e3938f Mon Sep 17 00:00:00 2001
From: Lester Hedges <lester.hedges@gmail.com>
Date: Wed, 25 Mar 2026 16:06:39 +0000
Subject: [PATCH] Normalise lambda and lambda_values as :.5f strings.

---
 src/somd2/runner/_base.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/somd2/runner/_base.py b/src/somd2/runner/_base.py
index 1c650c9..b351054 100644
--- a/src/somd2/runner/_base.py
+++ b/src/somd2/runner/_base.py
@@ -1763,14 +1763,14 @@ def _checkpoint(
                 "attrs": df.attrs,
                 "somd2 version": __version__,
                 "sire version": f"{_sire_version}+{_sire_revisionid}",
-                "lambda": str(lam),
+                "lambda": f"{lam:.5f}",
                 "speed": speed,
                 "temperature": str(self._config.temperature.value()),
             }
 
             # Add the lambda gradient if available.
             if lambda_grad is not None:
-                metadata["lambda_grad"] = lambda_grad
+                metadata["lambda_grad"] = [f"{v:.5f}" for v in lambda_grad]
 
             if is_final_block:
                 # Save the end-state GCMC topologies for trajectory analysis and visualisation.