From ddb1715c405f29f74f5c0b650b7b90872dbd878c Mon Sep 17 00:00:00 2001
From: Andreas Stefl <stefl.andreas@gmail.com>
Date: Thu, 4 Apr 2024 18:23:26 +0200
Subject: [PATCH] chore: Improved debugging outputs for `GainMatrixSmoother`
 (#3077)

IMO useful debugging logs
---
 Core/src/TrackFitting/GainMatrixSmoother.cpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/Core/src/TrackFitting/GainMatrixSmoother.cpp b/Core/src/TrackFitting/GainMatrixSmoother.cpp
index d41169a79dc1..fb56eb925fb5 100644
--- a/Core/src/TrackFitting/GainMatrixSmoother.cpp
+++ b/Core/src/TrackFitting/GainMatrixSmoother.cpp
@@ -35,8 +35,16 @@ Result<void> GainMatrixSmoother::calculate(
                   predictedCovariance(prev_ts).inverse();
 
   if (G.hasNaN()) {
-    // error = KalmanFitterError::SmoothFailed;  // set to error
-    // return false;                             // abort execution
+    ACTS_VERBOSE("Gain smoothing matrix G has NaNs");
+
+    ACTS_VERBOSE("Filtered covariance:\n" << filteredCovariance(ts));
+    ACTS_VERBOSE("Jacobian:\n" << jacobian(prev_ts));
+    ACTS_VERBOSE("Predicted covariance:\n" << predictedCovariance(prev_ts));
+    ACTS_VERBOSE("Inverse of predicted covariance:\n"
+                 << predictedCovariance(prev_ts).inverse());
+
+    ACTS_VERBOSE("Gain smoothing matrix G:\n" << G);
+
     return KalmanFitterError::SmoothFailed;
   }