diff --git a/gtsam/geometry/Rot2.h b/gtsam/geometry/Rot2.h
index fb54156df..65dd5f609 100644
--- a/gtsam/geometry/Rot2.h
+++ b/gtsam/geometry/Rot2.h
@@ -119,12 +119,12 @@ namespace gtsam {
 
     /// Left-trivialized derivative of the exponential map
     static Matrix ExpmapDerivative(const Vector& /*v*/) {
-      return Vector::Ones(1);
+      return I_1x1;
     }
 
     /// Left-trivialized derivative inverse of the exponential map
     static Matrix LogmapDerivative(const Vector& /*v*/) {
-      return Vector::Ones(1);
+      return I_1x1;
     }
 
     // Chart at origin simply uses exponential map and its inverse
diff --git a/gtsam_unstable/linear/tests/testQPSolver.cpp b/gtsam_unstable/linear/tests/testQPSolver.cpp
index 9a67cbb53..7442540f5 100644
--- a/gtsam_unstable/linear/tests/testQPSolver.cpp
+++ b/gtsam_unstable/linear/tests/testQPSolver.cpp
@@ -26,7 +26,7 @@ using namespace std;
 using namespace gtsam;
 using namespace gtsam::symbol_shorthand;
 
-const Matrix One = Matrix::Ones(1,1);
+const Matrix One = I_1x1;
 
 /* ************************************************************************* */
 // Create test graph according to Forst10book_pg171Ex5
@@ -38,14 +38,14 @@ QP createTestCase() {
   //        0.5*x1'*G11*x1 + x1'*G12*x2 + 0.5*x2'*G22*x2 - x1'*g1 - x2'*g2 + 0.5*f
   // Hence, we have G11=2, G12 = -1, g1 = +3, G22 = 2, g2 = 0, f = 10
   qp.cost.push_back(
-      HessianFactor(X(1), X(2), 2.0 * Matrix::Ones(1, 1), -Matrix::Ones(1, 1), 3.0 * Vector::Ones(1),
+      HessianFactor(X(1), X(2), 2.0 * Matrix::Ones(1, 1), -Matrix::Ones(1, 1), 3.0 * I_1x1,
           2.0 * Matrix::Ones(1, 1), Z_1x1, 10.0));
 
   // Inequality constraints
-  qp.inequalities.push_back(LinearInequality(X(1), Matrix::Ones(1,1), X(2), Matrix::Ones(1,1), 2, 0)); // x1 + x2 <= 2 --> x1 + x2 -2 <= 0, --> b=2
-  qp.inequalities.push_back(LinearInequality(X(1), -Matrix::Ones(1,1), 0, 1));                 // -x1     <= 0
-  qp.inequalities.push_back(LinearInequality(X(2), -Matrix::Ones(1,1), 0, 2));                 //    -x2  <= 0
-  qp.inequalities.push_back(LinearInequality(X(1), Matrix::Ones(1,1), 1.5, 3));                // x1      <= 3/2
+  qp.inequalities.push_back(LinearInequality(X(1), I_1x1, X(2), I_1x1, 2, 0)); // x1 + x2 <= 2 --> x1 + x2 -2 <= 0, --> b=2
+  qp.inequalities.push_back(LinearInequality(X(1), -I_1x1, 0, 1));                 // -x1     <= 0
+  qp.inequalities.push_back(LinearInequality(X(2), -I_1x1, 0, 2));                 //    -x2  <= 0
+  qp.inequalities.push_back(LinearInequality(X(1), I_1x1, 1.5, 3));                // x1      <= 3/2
 
   return qp;
 }
@@ -110,8 +110,8 @@ TEST(QPSolver, dual) {
 
   // Initials values
   VectorValues initialValues;
-  initialValues.insert(X(1), Vector::Ones(1));
-  initialValues.insert(X(2), Vector::Ones(1));
+  initialValues.insert(X(1), I_1x1);
+  initialValues.insert(X(2), I_1x1);
 
   QPSolver solver(qp);
 
@@ -219,8 +219,8 @@ QP createTestMatlabQPEx() {
   //        0.5*x1'*G11*x1 + x1'*G12*x2 + 0.5*x2'*G22*x2 - x1'*g1 - x2'*g2 + 0.5*f
   // Hence, we have G11=1, G12 = -1, g1 = +2, G22 = 2, g2 = +6, f = 0
   qp.cost.push_back(
-      HessianFactor(X(1), X(2), 1.0 * Matrix::Ones(1,1), -Matrix::Ones(1, 1), 2.0 * Vector::Ones(1),
-          2.0 * Matrix::Ones(1, 1), 6 * Vector::Ones(1), 1000.0));
+      HessianFactor(X(1), X(2), 1.0 * I_1x1, -Matrix::Ones(1, 1), 2.0 * I_1x1,
+          2.0 * Matrix::Ones(1, 1), 6 * I_1x1, 1000.0));
 
   // Inequality constraints
   qp.inequalities.push_back(LinearInequality(X(1), One, X(2), One, 2, 0));      // x1 + x2 <= 2
@@ -251,8 +251,8 @@ TEST(QPSolver, optimizeMatlabEx) {
 QP createTestNocedal06bookEx16_4() {
   QP qp;
 
-  qp.cost.push_back(JacobianFactor(X(1), Matrix::Ones(1, 1), Vector::Ones(1)));
-  qp.cost.push_back(JacobianFactor(X(2), Matrix::Ones(1, 1), 2.5 * Vector::Ones(1)));
+  qp.cost.push_back(JacobianFactor(X(1), Matrix::Ones(1, 1), I_1x1));
+  qp.cost.push_back(JacobianFactor(X(2), Matrix::Ones(1, 1), 2.5 * I_1x1));
 
   // Inequality constraints
   qp.inequalities.push_back(LinearInequality(X(1), -One, X(2), 2 * One, 2, 0));
diff --git a/tests/testBoundingConstraint.cpp b/tests/testBoundingConstraint.cpp
index 064deca5b..b0b748d95 100644
--- a/tests/testBoundingConstraint.cpp
+++ b/tests/testBoundingConstraint.cpp
@@ -54,8 +54,8 @@ TEST( testBoundingConstraint, unary_basics_inactive1 ) {
   EXPECT_DOUBLES_EQUAL(2.0, constraint2.threshold(), tol);
   EXPECT(constraint1.isGreaterThan());
   EXPECT(constraint2.isGreaterThan());
-  EXPECT(assert_equal(Vector::Ones(1), constraint1.evaluateError(pt1), tol));
-  EXPECT(assert_equal(Vector::Ones(1), constraint2.evaluateError(pt1), tol));
+  EXPECT(assert_equal(I_1x1, constraint1.evaluateError(pt1), tol));
+  EXPECT(assert_equal(I_1x1, constraint2.evaluateError(pt1), tol));
   EXPECT(assert_equal(Z_1x1, constraint1.unwhitenedError(config), tol));
   EXPECT(assert_equal(Z_1x1, constraint2.unwhitenedError(config), tol));
   EXPECT_DOUBLES_EQUAL(0.0, constraint1.error(config), tol);
@@ -103,10 +103,10 @@ TEST( testBoundingConstraint, unary_basics_active2 ) {
   config.insert(key, pt1);
   EXPECT(constraint3.active(config));
   EXPECT(constraint4.active(config));
-  EXPECT(assert_equal(-1.0 * Vector::Ones(1), constraint3.evaluateError(pt1), tol));
-  EXPECT(assert_equal(-1.0 * Vector::Ones(1), constraint4.evaluateError(pt1), tol));
-  EXPECT(assert_equal(-1.0 * Vector::Ones(1), constraint3.unwhitenedError(config), tol));
-  EXPECT(assert_equal(-1.0 * Vector::Ones(1), constraint4.unwhitenedError(config), tol));
+  EXPECT(assert_equal(-1.0 * I_1x1, constraint3.evaluateError(pt1), tol));
+  EXPECT(assert_equal(-1.0 * I_1x1, constraint4.evaluateError(pt1), tol));
+  EXPECT(assert_equal(-1.0 * I_1x1, constraint3.unwhitenedError(config), tol));
+  EXPECT(assert_equal(-1.0 * I_1x1, constraint4.unwhitenedError(config), tol));
   EXPECT_DOUBLES_EQUAL(5.0, constraint3.error(config), tol);
   EXPECT_DOUBLES_EQUAL(5.0, constraint4.error(config), tol);
 }
@@ -188,9 +188,9 @@ TEST( testBoundingConstraint, MaxDistance_basics) {
   EXPECT(rangeBound.dim() == 1);
 
   EXPECT(assert_equal((Vector(1) << 2.0).finished(), rangeBound.evaluateError(pt1, pt1)));
-  EXPECT(assert_equal(Vector::Ones(1), rangeBound.evaluateError(pt1, pt2)));
+  EXPECT(assert_equal(I_1x1, rangeBound.evaluateError(pt1, pt2)));
   EXPECT(assert_equal(Z_1x1, rangeBound.evaluateError(pt1, pt3)));
-  EXPECT(assert_equal(-1.0*Vector::Ones(1), rangeBound.evaluateError(pt1, pt4)));
+  EXPECT(assert_equal(-1.0*I_1x1, rangeBound.evaluateError(pt1, pt4)));
 
   Values config1;
   config1.insert(key1, pt1);
@@ -213,7 +213,7 @@ TEST( testBoundingConstraint, MaxDistance_basics) {
 
   config1.update(key2, pt4);
   EXPECT(rangeBound.active(config1));
-  EXPECT(assert_equal(-1.0*Vector::Ones(1), rangeBound.unwhitenedError(config1)));
+  EXPECT(assert_equal(-1.0*I_1x1, rangeBound.unwhitenedError(config1)));
   EXPECT_DOUBLES_EQUAL(0.5*mu, rangeBound.error(config1), tol);
 }