diff --git a/bench/bench_norm.cpp b/bench/bench_norm.cpp
new file mode 100644
index 0000000..806db29
--- /dev/null
+++ b/bench/bench_norm.cpp
@@ -0,0 +1,345 @@
+#include <typeinfo>
+#include <iostream>
+#include <Eigen/Core>
+#include "BenchTimer.h"
+using namespace Eigen;
+using namespace std;
+
+template<typename T>
+EIGEN_DONT_INLINE typename T::Scalar sqsumNorm(const T& v)
+{
+  return v.norm();
+}
+
+template<typename T>
+EIGEN_DONT_INLINE typename T::Scalar hypotNorm(const T& v)
+{
+  return v.hypotNorm();
+}
+
+template<typename T>
+EIGEN_DONT_INLINE typename T::Scalar blueNorm(const T& v)
+{
+  return v.blueNorm();
+}
+
+template<typename T>
+EIGEN_DONT_INLINE typename T::Scalar lapackNorm(T& v)
+{
+  typedef typename T::Scalar Scalar;
+  int n = v.size();
+  Scalar scale = 0;
+  Scalar ssq = 1;
+  for (int i=0;i<n;++i)
+  {
+    Scalar ax = internal::abs(v.coeff(i));
+    if (scale >= ax)
+    {
+      ssq += internal::abs2(ax/scale);
+    }
+    else
+    {
+      ssq = Scalar(1) + ssq * internal::abs2(scale/ax);
+      scale = ax;
+    }
+  }
+  return scale * internal::sqrt(ssq);
+}
+
+template<typename T>
+EIGEN_DONT_INLINE typename T::Scalar twopassNorm(T& v)
+{
+  typedef typename T::Scalar Scalar;
+  Scalar s = v.cwise().abs().maxCoeff();
+  return s*(v/s).norm();
+}
+
+template<typename T>
+EIGEN_DONT_INLINE typename T::Scalar bl2passNorm(T& v)
+{
+  return v.stableNorm();
+}
+
+template<typename T>
+EIGEN_DONT_INLINE typename T::Scalar divacNorm(T& v)
+{
+  int n =v.size() / 2;
+  for (int i=0;i<n;++i)
+    v(i) = v(2*i)*v(2*i) + v(2*i+1)*v(2*i+1);
+  n = n/2;
+  while (n>0)
+  {
+    for (int i=0;i<n;++i)
+      v(i) = v(2*i) + v(2*i+1);
+    n = n/2;
+  }
+  return internal::sqrt(v(0));
+}
+
+#ifdef EIGEN_VECTORIZE
+Packet4f internal::plt(const Packet4f& a, Packet4f& b) { return _mm_cmplt_ps(a,b); }
+Packet2d internal::plt(const Packet2d& a, Packet2d& b) { return _mm_cmplt_pd(a,b); }
+
+Packet4f internal::pandnot(const Packet4f& a, Packet4f& b) { return _mm_andnot_ps(a,b); }
+Packet2d internal::pandnot(const Packet2d& a, Packet2d& b) { return _mm_andnot_pd(a,b); }
+#endif
+
+template<typename T>
+EIGEN_DONT_INLINE typename T::Scalar pblueNorm(const T& v)
+{
+  #ifndef EIGEN_VECTORIZE
+  return v.blueNorm();
+  #else
+  typedef typename T::Scalar Scalar;
+
+  static int nmax = 0;
+  static Scalar b1, b2, s1m, s2m, overfl, rbig, relerr;
+  int n;
+
+  if(nmax <= 0)
+  {
+    int nbig, ibeta, it, iemin, iemax, iexp;
+    Scalar abig, eps;
+
+    nbig  = std::numeric_limits<int>::max();            // largest integer
+    ibeta = std::numeric_limits<Scalar>::radix; //NumTraits<Scalar>::Base;                    // base for floating-point numbers
+    it    = std::numeric_limits<Scalar>::digits; //NumTraits<Scalar>::Mantissa;                // number of base-beta digits in mantissa
+    iemin = std::numeric_limits<Scalar>::min_exponent;  // minimum exponent
+    iemax = std::numeric_limits<Scalar>::max_exponent;  // maximum exponent
+    rbig  = std::numeric_limits<Scalar>::max();         // largest floating-point number
+
+    // Check the basic machine-dependent constants.
+    if(iemin > 1 - 2*it || 1+it>iemax || (it==2 && ibeta<5)
+      || (it<=4 && ibeta <= 3 ) || it<2)
+    {
+      eigen_assert(false && "the algorithm cannot be guaranteed on this computer");
+    }
+    iexp  = -((1-iemin)/2);
+    b1    = std::pow(ibeta, iexp);  // lower boundary of midrange
+    iexp  = (iemax + 1 - it)/2;
+    b2    = std::pow(ibeta,iexp);   // upper boundary of midrange
+
+    iexp  = (2-iemin)/2;
+    s1m   = std::pow(ibeta,iexp);   // scaling factor for lower range
+    iexp  = - ((iemax+it)/2);
+    s2m   = std::pow(ibeta,iexp);   // scaling factor for upper range
+
+    overfl  = rbig*s2m;          // overfow boundary for abig
+    eps     = std::pow(ibeta, 1-it);
+    relerr  = internal::sqrt(eps);      // tolerance for neglecting asml
+    abig    = 1.0/eps - 1.0;
+    if (Scalar(nbig)>abig)  nmax = abig;  // largest safe n
+    else                    nmax = nbig;
+  }
+
+  typedef typename internal::packet_traits<Scalar>::type Packet;
+  const int ps = internal::packet_traits<Scalar>::size;
+  Packet pasml = internal::pset1(Scalar(0));
+  Packet pamed = internal::pset1(Scalar(0));
+  Packet pabig = internal::pset1(Scalar(0));
+  Packet ps2m = internal::pset1(s2m);
+  Packet ps1m = internal::pset1(s1m);
+  Packet pb2  = internal::pset1(b2);
+  Packet pb1  = internal::pset1(b1);
+  for(int j=0; j<v.size(); j+=ps)
+  {
+    Packet ax = internal::pabs(v.template packet<Aligned>(j));
+    Packet ax_s2m = internal::pmul(ax,ps2m);
+    Packet ax_s1m = internal::pmul(ax,ps1m);
+    Packet maskBig = internal::plt(pb2,ax);
+    Packet maskSml = internal::plt(ax,pb1);
+
+//     Packet maskMed = internal::pand(maskSml,maskBig);
+//     Packet scale = internal::pset1(Scalar(0));
+//     scale = internal::por(scale, internal::pand(maskBig,ps2m));
+//     scale = internal::por(scale, internal::pand(maskSml,ps1m));
+//     scale = internal::por(scale, internal::pandnot(internal::pset1(Scalar(1)),maskMed));
+//     ax = internal::pmul(ax,scale);
+//     ax = internal::pmul(ax,ax);
+//     pabig = internal::padd(pabig, internal::pand(maskBig, ax));
+//     pasml = internal::padd(pasml, internal::pand(maskSml, ax));
+//     pamed = internal::padd(pamed, internal::pandnot(ax,maskMed));
+
+
+    pabig = internal::padd(pabig, internal::pand(maskBig, internal::pmul(ax_s2m,ax_s2m)));
+    pasml = internal::padd(pasml, internal::pand(maskSml, internal::pmul(ax_s1m,ax_s1m)));
+    pamed = internal::padd(pamed, internal::pandnot(internal::pmul(ax,ax),internal::pand(maskSml,maskBig)));
+  }
+  Scalar abig = internal::predux(pabig);
+  Scalar asml = internal::predux(pasml);
+  Scalar amed = internal::predux(pamed);
+  if(abig > Scalar(0))
+  {
+    abig = internal::sqrt(abig);
+    if(abig > overfl)
+    {
+      eigen_assert(false && "overflow");
+      return rbig;
+    }
+    if(amed > Scalar(0))
+    {
+      abig = abig/s2m;
+      amed = internal::sqrt(amed);
+    }
+    else
+    {
+      return abig/s2m;
+    }
+
+  }
+  else if(asml > Scalar(0))
+  {
+    if (amed > Scalar(0))
+    {
+      abig = internal::sqrt(amed);
+      amed = internal::sqrt(asml) / s1m;
+    }
+    else
+    {
+      return internal::sqrt(asml)/s1m;
+    }
+  }
+  else
+  {
+    return internal::sqrt(amed);
+  }
+  asml = std::min(abig, amed);
+  abig = std::max(abig, amed);
+  if(asml <= abig*relerr)
+    return abig;
+  else
+    return abig * internal::sqrt(Scalar(1) + internal::abs2(asml/abig));
+  #endif
+}
+
+#define BENCH_PERF(NRM) { \
+  Eigen::BenchTimer tf, td, tcf; tf.reset(); td.reset(); tcf.reset();\
+  for (int k=0; k<tries; ++k) { \
+    tf.start(); \
+    for (int i=0; i<iters; ++i) NRM(vf); \
+    tf.stop(); \
+  } \
+  for (int k=0; k<tries; ++k) { \
+    td.start(); \
+    for (int i=0; i<iters; ++i) NRM(vd); \
+    td.stop(); \
+  } \
+  for (int k=0; k<std::max(1,tries/3); ++k) { \
+    tcf.start(); \
+    for (int i=0; i<iters; ++i) NRM(vcf); \
+    tcf.stop(); \
+  } \
+  std::cout << #NRM << "\t" << tf.value() << "   " << td.value() <<  "    " << tcf.value() << "\n"; \
+}
+
+void check_accuracy(double basef, double based, int s)
+{
+  double yf = basef * internal::abs(internal::random<double>());
+  double yd = based * internal::abs(internal::random<double>());
+  VectorXf vf = VectorXf::Ones(s) * yf;
+  VectorXd vd = VectorXd::Ones(s) * yd;
+
+  std::cout << "reference\t" << internal::sqrt(double(s))*yf << "\t" << internal::sqrt(double(s))*yd << "\n";
+  std::cout << "sqsumNorm\t" << sqsumNorm(vf) << "\t" << sqsumNorm(vd) << "\n";
+  std::cout << "hypotNorm\t" << hypotNorm(vf) << "\t" << hypotNorm(vd) << "\n";
+  std::cout << "blueNorm\t" << blueNorm(vf) << "\t" << blueNorm(vd) << "\n";
+  std::cout << "pblueNorm\t" << pblueNorm(vf) << "\t" << pblueNorm(vd) << "\n";
+  std::cout << "lapackNorm\t" << lapackNorm(vf) << "\t" << lapackNorm(vd) << "\n";
+  std::cout << "twopassNorm\t" << twopassNorm(vf) << "\t" << twopassNorm(vd) << "\n";
+  std::cout << "bl2passNorm\t" << bl2passNorm(vf) << "\t" << bl2passNorm(vd) << "\n";
+}
+
+void check_accuracy_var(int ef0, int ef1, int ed0, int ed1, int s)
+{
+  VectorXf vf(s);
+  VectorXd vd(s);
+  for (int i=0; i<s; ++i)
+  {
+    vf[i] = internal::abs(internal::random<double>()) * std::pow(double(10), internal::random<int>(ef0,ef1));
+    vd[i] = internal::abs(internal::random<double>()) * std::pow(double(10), internal::random<int>(ed0,ed1));
+  }
+
+  //std::cout << "reference\t" << internal::sqrt(double(s))*yf << "\t" << internal::sqrt(double(s))*yd << "\n";
+  std::cout << "sqsumNorm\t"  << sqsumNorm(vf)  << "\t" << sqsumNorm(vd)  << "\t" << sqsumNorm(vf.cast<long double>()) << "\t" << sqsumNorm(vd.cast<long double>()) << "\n";
+  std::cout << "hypotNorm\t"  << hypotNorm(vf)  << "\t" << hypotNorm(vd)  << "\t" << hypotNorm(vf.cast<long double>()) << "\t" << hypotNorm(vd.cast<long double>()) << "\n";
+  std::cout << "blueNorm\t"   << blueNorm(vf)   << "\t" << blueNorm(vd)   << "\t" << blueNorm(vf.cast<long double>()) << "\t" << blueNorm(vd.cast<long double>()) << "\n";
+  std::cout << "pblueNorm\t"  << pblueNorm(vf)  << "\t" << pblueNorm(vd)  << "\t" << blueNorm(vf.cast<long double>()) << "\t" << blueNorm(vd.cast<long double>()) << "\n";
+  std::cout << "lapackNorm\t" << lapackNorm(vf) << "\t" << lapackNorm(vd) << "\t" << lapackNorm(vf.cast<long double>()) << "\t" << lapackNorm(vd.cast<long double>()) << "\n";
+  std::cout << "twopassNorm\t" << twopassNorm(vf) << "\t" << twopassNorm(vd) << "\t" << twopassNorm(vf.cast<long double>()) << "\t" << twopassNorm(vd.cast<long double>()) << "\n";
+//   std::cout << "bl2passNorm\t" << bl2passNorm(vf) << "\t" << bl2passNorm(vd) << "\t" << bl2passNorm(vf.cast<long double>()) << "\t" << bl2passNorm(vd.cast<long double>()) << "\n";
+}
+
+int main(int argc, char** argv)
+{
+  int tries = 10;
+  int iters = 100000;
+  double y = 1.1345743233455785456788e12 * internal::random<double>();
+  VectorXf v = VectorXf::Ones(1024) * y;
+
+// return 0;
+  int s = 10000;
+  double basef_ok = 1.1345743233455785456788e15;
+  double based_ok = 1.1345743233455785456788e95;
+
+  double basef_under = 1.1345743233455785456788e-27;
+  double based_under = 1.1345743233455785456788e-303;
+
+  double basef_over = 1.1345743233455785456788e+27;
+  double based_over = 1.1345743233455785456788e+302;
+
+  std::cout.precision(20);
+
+  std::cerr << "\nNo under/overflow:\n";
+  check_accuracy(basef_ok, based_ok, s);
+
+  std::cerr << "\nUnderflow:\n";
+  check_accuracy(basef_under, based_under, s);
+
+  std::cerr << "\nOverflow:\n";
+  check_accuracy(basef_over, based_over, s);
+
+  std::cerr << "\nVarying (over):\n";
+  for (int k=0; k<1; ++k)
+  {
+    check_accuracy_var(20,27,190,302,s);
+    std::cout << "\n";
+  }
+
+  std::cerr << "\nVarying (under):\n";
+  for (int k=0; k<1; ++k)
+  {
+    check_accuracy_var(-27,20,-302,-190,s);
+    std::cout << "\n";
+  }
+
+  std::cout.precision(4);
+  std::cerr << "Performance (out of cache):\n";
+  {
+    int iters = 1;
+    VectorXf vf = VectorXf::Random(1024*1024*32) * y;
+    VectorXd vd = VectorXd::Random(1024*1024*32) * y;
+    VectorXcf vcf = VectorXcf::Random(1024*1024*32) * y;
+    BENCH_PERF(sqsumNorm);
+    BENCH_PERF(blueNorm);
+//     BENCH_PERF(pblueNorm);
+//     BENCH_PERF(lapackNorm);
+//     BENCH_PERF(hypotNorm);
+//     BENCH_PERF(twopassNorm);
+    BENCH_PERF(bl2passNorm);
+  }
+
+  std::cerr << "\nPerformance (in cache):\n";
+  {
+    int iters = 100000;
+    VectorXf vf = VectorXf::Random(512) * y;
+    VectorXd vd = VectorXd::Random(512) * y;
+    VectorXcf vcf = VectorXcf::Random(512) * y;
+    BENCH_PERF(sqsumNorm);
+    BENCH_PERF(blueNorm);
+//     BENCH_PERF(pblueNorm);
+//     BENCH_PERF(lapackNorm);
+//     BENCH_PERF(hypotNorm);
+//     BENCH_PERF(twopassNorm);
+    BENCH_PERF(bl2passNorm);
+  }
+}