From afa43e13c8701d99d3e01c79fc0ab5fb746aae78 Mon Sep 17 00:00:00 2001
From: Francis Couture-Harpin <git@compilade.net>
Date: Sun, 3 Aug 2025 18:03:53 -0400
Subject: [PATCH] imatrix : add warning when suffix is not .gguf for GGUF
 imatrix

---
 tools/imatrix/imatrix.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/imatrix/imatrix.cpp b/tools/imatrix/imatrix.cpp
index 9ceceb478d..aaf52eb742 100644
--- a/tools/imatrix/imatrix.cpp
+++ b/tools/imatrix/imatrix.cpp
@@ -512,7 +512,11 @@ void IMatrixCollector::save_imatrix(int32_t n_chunk) const {
         this->save_imatrix_legacy(n_chunk);
         return;
     }
-    // else, default to GGUF imatrix
+    if (!string_ends_with(fname, ".gguf")) {
+        // allowed, but hopefully this raises awareness
+        LOG_WRN("\n%s: saving imatrix using GGUF format with a different suffix than .gguf\n", __func__);
+        LOG_WRN("%s: if you want the previous imatrix format, use --output-format dat\n", __func__);
+    }
 
     if (n_chunk > 0) {
         fname += ".at_";