diff --git a/gtsam/base/Matrix.cpp b/gtsam/base/Matrix.cpp
index d813e43a6..64df12918 100644
--- a/gtsam/base/Matrix.cpp
+++ b/gtsam/base/Matrix.cpp
@@ -105,6 +105,15 @@ bool assert_equal(const Matrix& expected, const Matrix& actual, double tol) {
   return false;
 }
 
+/* ************************************************************************* */
+bool assert_inequal(const Matrix& A, const Matrix& B, double tol) {
+  if (!equal_with_abs_tol(A,B,tol)) return true;
+  cout << "Erroneously equal:" << endl;
+  print(A, "A = ");
+  print(B, "B = ");
+  return false;
+}
+
 /* ************************************************************************* */
 bool assert_equal(const std::list<Matrix>& As, const std::list<Matrix>& Bs, double tol) {
   if (As.size() != Bs.size()) return false;
diff --git a/gtsam/base/Matrix.h b/gtsam/base/Matrix.h
index 77af3d058..297e77852 100644
--- a/gtsam/base/Matrix.h
+++ b/gtsam/base/Matrix.h
@@ -134,6 +134,11 @@ inline bool operator!=(const Matrix& A, const Matrix& B) {
  */
 GTSAM_EXPORT bool assert_equal(const Matrix& A, const Matrix& B, double tol = 1e-9);
 
+/**
+ * inequals with an tolerance, prints out message if within tolerance
+ */
+GTSAM_EXPORT bool assert_inequal(const Matrix& A, const Matrix& B, double tol = 1e-9);
+
 /**
  * equals with an tolerance, prints out message if unequal
  */