diff --git a/coord/ops.hpp b/coord/ops.hpp
index e6cf7c1a..33d172a0 100644
--- a/coord/ops.hpp
+++ b/coord/ops.hpp
@@ -1491,7 +1491,23 @@ namespace cruft {
             val
         );
     }
-};
+
+
+    //-------------------------------------------------------------------------
+    template <
+        std::size_t S,
+        typename T,
+        typename = std::enable_if_t<std::is_floating_point_v<T>>
+    >
+    vector<S,bool>
+    isfinite (vector<S,T> const &val)
+    {
+        vector<S,bool> res;
+        for (std::size_t i = 0; i < S; ++i)
+            res[i] = std::isfinite (val[i]);
+        return res;
+    }
+}
 
 
 ///////////////////////////////////////////////////////////////////////////////