diff --git a/include/mcl/ec.hpp b/include/mcl/ec.hpp
index bd91934..7a64868 100644
--- a/include/mcl/ec.hpp
+++ b/include/mcl/ec.hpp
@@ -1196,7 +1196,7 @@ public:
 		@note &z != xVec[i]
 	*/
 private:
-	template<size_t N = 32, class tag, size_t maxBitSize, template<class _tag, size_t _maxBitSize>class FpT>
+	template<size_t N, class tag, size_t maxBitSize, template<class _tag, size_t _maxBitSize>class FpT>
 	static inline size_t addMulVecN(EcT& z, const EcT *xVec, const FpT<tag, maxBitSize> *yVec, size_t n)
 	{
 		if (n > N) n = N;
@@ -1236,7 +1236,7 @@ public:
 		r.clear();
 		while (n > 0) {
 			EcT t;
-			size_t done = addMulVecN(t, xVec, yVec, n);
+			size_t done = addMulVecN<32>(t, xVec, yVec, n);
 			r += t;
 			xVec += done;
 			yVec += done;
diff --git a/test/bls12_test.cpp b/test/bls12_test.cpp
index c86fed2..6aac204 100644
--- a/test/bls12_test.cpp
+++ b/test/bls12_test.cpp
@@ -384,7 +384,7 @@ CYBOZU_TEST_AUTO(naive)
 		testPairing(P, Q, ts.e);
 		testPrecomputed(P, Q);
 		testMillerLoop2(P, Q);
-		testCommon();
+		testCommon(P, Q);
 		testBench(P, Q);
 	}
 	int count = (int)clk.getCount();
diff --git a/test/bn384_test.cpp b/test/bn384_test.cpp
index a8c7cdb..e248d48 100644
--- a/test/bn384_test.cpp
+++ b/test/bn384_test.cpp
@@ -40,7 +40,7 @@ void testCurve(const mcl::CurveParam& cp)
 	pairing(e2, aP, bQ);
 	GT::pow(e1, e1, a * b);
 	CYBOZU_TEST_EQUAL(e1, e2);
-	testCommon();
+	testCommon(P, Q);
 	testBench(P, Q);
 	testSquareRoot();
 	testLagrange();
diff --git a/test/bn512_test.cpp b/test/bn512_test.cpp
index db2aff1..ebbc7c0 100644
--- a/test/bn512_test.cpp
+++ b/test/bn512_test.cpp
@@ -34,7 +34,7 @@ void testCurve(const mcl::CurveParam& cp)
 	pairing(e2, aP, bQ);
 	GT::pow(e1, e1, a * b);
 	CYBOZU_TEST_EQUAL(e1, e2);
-	testCommon();
+	testCommon(P, Q);
 	testBench(P, Q);
 	testSquareRoot();
 	testLagrange();
diff --git a/test/bn_test.cpp b/test/bn_test.cpp
index a2557a3..397f9a1 100644
--- a/test/bn_test.cpp
+++ b/test/bn_test.cpp
@@ -402,7 +402,7 @@ CYBOZU_TEST_AUTO(naive)
 		testPrecomputed(P, Q);
 		testMillerLoop2(P, Q);
 		testMillerLoopVec();
-		testCommon();
+		testCommon(P, Q);
 		testBench(P, Q);
 		benchAddDblG1();
 		benchAddDblG2();
diff --git a/test/common_test.hpp b/test/common_test.hpp
index 400b523..e5378e9 100644
--- a/test/common_test.hpp
+++ b/test/common_test.hpp
@@ -1,27 +1,44 @@
-void testMulVec()
+template<class G, class F>
+void naiveMulVec(G& out, const G *xVec, const F *yVec, size_t n)
 {
-	using namespace mcl::bn;
-	const size_t n = 3;
-	G1 xVec[n];
-	Fr yVec[n];
-	G1 ok;
-	ok.clear();
-	char c = 'a';
+	G r, t;
+	r.clear();
 	for (size_t i = 0; i < n; i++) {
-		hashAndMapToG1(xVec[i], &c, 1);
+		G::mul(t, xVec[i], yVec[i]);
+		r += t;
+	}
+	out = r;
+}
+
+template<class G>
+void testMulVec(const G& P)
+{
+	using namespace mcl::bn;
+	const int N = 33;
+	G xVec[N];
+	mcl::bn::Fr yVec[N];
+
+	for (size_t i = 0; i < N; i++) {
+		G::mul(xVec[i], P, i + 3);
 		yVec[i].setByCSPRNG();
-		G1 t;
-		G1::mul(t, xVec[i], yVec[i]);
-		ok += t;
 	}
-	G1 z;
-	G1::mulVec(z, xVec, yVec, n);
-	CYBOZU_TEST_EQUAL(z, ok);
-	CYBOZU_BENCH_C("mulVec(new)", 1000, G1::mulVec, z, xVec, yVec, n);
-	CYBOZU_BENCH_C("mulVec(old)", 1000, G1::mulVec, z, xVec, yVec, n, true);
+	const size_t nTbl[] = { 1, 2, 3, 5, 30, 31, 32, 33 };
+	const int C = 400;
+	for (size_t i = 0; i < CYBOZU_NUM_OF_ARRAY(nTbl); i++) {
+		const size_t n = nTbl[i];
+		G Q1, Q2;
+		CYBOZU_TEST_ASSERT(n <= N);
+		naiveMulVec(Q1, xVec, yVec, n);
+		G::mulVec(Q2, xVec, yVec, n);
+		CYBOZU_TEST_EQUAL(Q1, Q2);
+		printf("n=%zd\n", n);
+		CYBOZU_BENCH_C("naive ", C, naiveMulVec, Q1, xVec, yVec, n);
+		CYBOZU_BENCH_C("mulVec", C, G::mulVec, Q1, xVec, yVec, n);
+	}
 }
 
-void testCommon()
+template<class G1, class G2>
+void testCommon(const G1& P, const G2&)
 {
-	testMulVec();
+	testMulVec(P);
 }