diff --git a/bench_nd.py b/bench_nd.py
index f532b0e207307034dbee59e81dee6a2f0fb03b9b..ab391751ddd601eb5872a5cee4cf68e4450e1575 100644
--- a/bench_nd.py
+++ b/bench_nd.py
@@ -5,7 +5,7 @@ import pypocketfft
 from time import time
 import matplotlib.pyplot as plt
 
-nthreads=0
+nthreads=1
 def _l2error(a,b):
     return np.sqrt(np.sum(np.abs(a-b)**2)/np.sum(np.abs(a)**2))
 
@@ -26,7 +26,7 @@ def bench_nd_fftn(ndim, nmax, ntry, tp, nrepeat, filename=""):
             b=pypocketfft.fftn(a,nthreads=nthreads)
             t1=time()
             tmin_pp = min(tmin_pp,t1-t0)
-        a2=pypocketfft.ifftn(b,fct=1./a.size)
+        a2=pypocketfft.ifftn(b,inorm=2)
         assert(_l2error(a,a2)<(2.5e-15 if tp=='c16' else 6e-7))
         res.append(tmin_pp/tmin_np)
     plt.title("t(pypocketfft / numpy 1.17), {}D, {}, max_extent={}".format(ndim, str(tp), nmax))
diff --git a/pocketfft_hdronly.h b/pocketfft_hdronly.h
index b467629c15307e15c3cd459a6f170d01af33bd8d..372ad2d41a05245476ab868be676f50fd9cff9cc 100644
--- a/pocketfft_hdronly.h
+++ b/pocketfft_hdronly.h
@@ -34,11 +34,11 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #define POCKETFFT_HDRONLY_H
 
 #ifndef __cplusplus
-#error This file is C++ and requires a C++ compiler
+#error This file is C++ and requires a C++ compiler.
 #endif
 
 #if !(__cplusplus >= 201103L || _MSVC_LANG+0L >= 201103L)
-#error This file requires at least C++11 support
+#error This file requires at least C++11 support.
 #endif
 
 #include <cmath>
@@ -48,9 +48,6 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <memory>
 #include <vector>
 #include <complex>
-#if defined(_WIN32)
-#include <malloc.h>
-#endif
 #ifdef POCKETFFT_OPENMP
 #include <omp.h>
 #endif
@@ -83,7 +80,7 @@ constexpr bool FORWARD  = true,
 #ifndef POCKETFFT_NO_VECTORS
 #define POCKETFFT_NO_VECTORS
 #if defined(__INTEL_COMPILER)
-// do nothing. This is necessary because this compiler also sets __GNUC__
+// do nothing. This is necessary because this compiler also sets __GNUC__.
 #elif defined(__clang__)
 #if __clang__>=5
 #undef POCKETFFT_NO_VECTORS
@@ -141,27 +138,19 @@ template<typename T> class arr
       }
     static void dealloc(T *ptr)
       { free(ptr); }
-#elif defined(_WIN32)
+#else // portable emulation
     static T *ralloc(size_t num)
       {
       if (num==0) return nullptr;
-      void *res = _aligned_malloc(num*sizeof(T), 64);
-      if (!res) throw bad_alloc();
-      return reinterpret_cast<T *>(res);
+      void *ptr = malloc(num*sizeof(T)+64);
+      if (!ptr) throw bad_alloc();
+      T *res = reinterpret_cast<T *>
+        ((reinterpret_cast<size_t>(ptr) & ~(size_t(63))) + 64);
+      (reinterpret_cast<void**>(res))[-1] = ptr;
+      return res;
       }
     static void dealloc(T *ptr)
-      { _aligned_free(ptr); }
-#else
-    static T *ralloc(size_t num)
-      {
-      if (num==0) return nullptr;
-      void *res(nullptr);
-      if (posix_memalign(&res, 64, num*sizeof(T))!=0)
-        throw bad_alloc();
-      return reinterpret_cast<T *>(res);
-      }
-    static void dealloc(T *ptr)
-      { free(ptr); }
+      { if (ptr) free((reinterpret_cast<void**>(ptr))[-1]); }
 #endif
 
   public:
diff --git a/pypocketfft.cc b/pypocketfft.cc
index 6fb321563b61ec91efef90b958f521ad430cbb88..fabe4a27d8e71652af70c674afe3b2284cfde83f 100644
--- a/pypocketfft.cc
+++ b/pypocketfft.cc
@@ -27,12 +27,16 @@ using namespace pocketfft;
 
 namespace py = pybind11;
 
+// Only instantiate long double transforms if they offer more precision
+using ldbl_t = typename std::conditional<
+  sizeof(long double)==sizeof(double), double, long double>::type;
+
 auto c64 = py::dtype("complex64");
 auto c128 = py::dtype("complex128");
-auto c256 = py::dtype("complex256");
+auto clong = py::dtype("longcomplex");
 auto f32 = py::dtype("float32");
 auto f64 = py::dtype("float64");
-auto f128 = py::dtype("float128");
+auto flong = py::dtype("longfloat");
 
 shape_t copy_shape(const py::array &arr)
   {
@@ -72,11 +76,29 @@ shape_t makeaxes(const py::array &in, py::object axes)
   auto dtype = arr.dtype(); \
   if (dtype.is(T1)) return func<double> args; \
   if (dtype.is(T2)) return func<float> args; \
-  if (dtype.is(T3)) return func<long double> args; \
+  if (dtype.is(T3)) return func<ldbl_t> args; \
   throw runtime_error("unsupported data type");
 
+template<typename T> T norm_fct(int inorm, size_t N)
+  {
+  if (inorm==0) return T(1);
+  if (inorm==2) return T(1/ldbl_t(N));
+  if (inorm==1) return T(1/sqrt(ldbl_t(N)));
+  throw invalid_argument("invalid value for inorm (must be 0, 1, or 2)");
+  }
+
+template<typename T> T norm_fct(int inorm, const shape_t &shape,
+  const shape_t &axes)
+  {
+  if (inorm==0) return T(1);
+  size_t N(1);
+  for (auto a: axes)
+    N *= shape[a];
+  return norm_fct<T>(inorm, N);
+  }
+
 template<typename T> py::array xfftn_internal(const py::array &in,
-  const shape_t &axes, long double fct, bool inplace, bool fwd, size_t nthreads)
+  const shape_t &axes, int inorm, bool inplace, bool fwd, size_t nthreads)
   {
   auto dims(copy_shape(in));
   py::array res = inplace ? in : py::array_t<complex<T>>(dims);
@@ -86,28 +108,29 @@ template<typename T> py::array xfftn_internal(const py::array &in,
   auto d_out=reinterpret_cast<complex<T> *>(res.mutable_data());
   {
   py::gil_scoped_release release;
-  c2c(dims, s_in, s_out, axes, fwd, d_in, d_out, T(fct), nthreads);
+  T fct = norm_fct<T>(inorm, dims, axes);
+  c2c(dims, s_in, s_out, axes, fwd, d_in, d_out, fct, nthreads);
   }
   return res;
   }
 
-py::array xfftn(const py::array &a, py::object axes, double fct, bool inplace,
-  bool fwd, size_t nthreads)
+py::array xfftn(const py::array &a, py::object axes, int inorm,
+  bool inplace, bool fwd, size_t nthreads)
   {
-  DISPATCH(a, c128, c64, c256, xfftn_internal, (a, makeaxes(a, axes), fct,
+  DISPATCH(a, c128, c64, clong, xfftn_internal, (a, makeaxes(a, axes), inorm,
            inplace, fwd, nthreads))
   }
 
-py::array fftn(const py::array &a, py::object axes, double fct, bool inplace,
-  size_t nthreads)
-  { return xfftn(a, axes, fct, inplace, true, nthreads); }
+py::array fftn(const py::array &a, py::object axes, int inorm,
+  bool inplace, size_t nthreads)
+  { return xfftn(a, axes, inorm, inplace, true, nthreads); }
 
-py::array ifftn(const py::array &a, py::object axes, double fct, bool inplace,
-  size_t nthreads)
-  { return xfftn(a, axes, fct, inplace, false, nthreads); }
+py::array ifftn(const py::array &a, py::object axes, int inorm,
+  bool inplace, size_t nthreads)
+  { return xfftn(a, axes, inorm, inplace, false, nthreads); }
 
 template<typename T> py::array rfftn_internal(const py::array &in,
-  py::object axes_, long double fct, size_t nthreads)
+  py::object axes_, int inorm, size_t nthreads)
   {
   auto axes = makeaxes(in, axes_);
   auto dims_in(copy_shape(in)), dims_out(dims_in);
@@ -119,19 +142,20 @@ template<typename T> py::array rfftn_internal(const py::array &in,
   auto d_out=reinterpret_cast<complex<T> *>(res.mutable_data());
   {
   py::gil_scoped_release release;
-  r2c(dims_in, s_in, s_out, axes, d_in, d_out, T(fct), nthreads);
+  T fct = norm_fct<T>(inorm, dims_in, axes);
+  r2c(dims_in, s_in, s_out, axes, d_in, d_out, fct, nthreads);
   }
   return res;
   }
 
-py::array rfftn(const py::array &in, py::object axes_, double fct,
+py::array rfftn(const py::array &in, py::object axes_, int inorm,
   size_t nthreads)
   {
-  DISPATCH(in, f64, f32, f128, rfftn_internal, (in, axes_, fct, nthreads))
+  DISPATCH(in, f64, f32, flong, rfftn_internal, (in, axes_, inorm, nthreads))
   }
 
 template<typename T> py::array xrfft_scipy(const py::array &in,
-  size_t axis, long double fct, bool inplace, bool fwd, size_t nthreads)
+  size_t axis, int inorm, bool inplace, bool fwd, size_t nthreads)
   {
   auto dims(copy_shape(in));
   py::array res = inplace ? in : py::array_t<T>(dims);
@@ -141,26 +165,27 @@ template<typename T> py::array xrfft_scipy(const py::array &in,
   auto d_out=reinterpret_cast<T *>(res.mutable_data());
   {
   py::gil_scoped_release release;
-  r2r_fftpack(dims, s_in, s_out, axis, fwd, d_in, d_out, T(fct), nthreads);
+  T fct = norm_fct<T>(inorm, dims[axis]);
+  r2r_fftpack(dims, s_in, s_out, axis, fwd, d_in, d_out, fct, nthreads);
   }
   return res;
   }
 
-py::array rfft_scipy(const py::array &in, size_t axis, double fct, bool inplace,
-  size_t nthreads)
+py::array rfft_scipy(const py::array &in, size_t axis, int inorm,
+  bool inplace, size_t nthreads)
   {
-  DISPATCH(in, f64, f32, f128, xrfft_scipy, (in, axis, fct, inplace, true,
+  DISPATCH(in, f64, f32, flong, xrfft_scipy, (in, axis, inorm, inplace, true,
     nthreads))
   }
 
-py::array irfft_scipy(const py::array &in, size_t axis, double fct,
+py::array irfft_scipy(const py::array &in, size_t axis, int inorm,
   bool inplace, size_t nthreads)
   {
-  DISPATCH(in, f64, f32, f128, xrfft_scipy, (in, axis, fct, inplace, false,
+  DISPATCH(in, f64, f32, flong, xrfft_scipy, (in, axis, inorm, inplace, false,
     nthreads))
   }
 template<typename T> py::array irfftn_internal(const py::array &in,
-  py::object axes_, size_t lastsize, long double fct, size_t nthreads)
+  py::object axes_, size_t lastsize, int inorm, size_t nthreads)
   {
   auto axes = makeaxes(in, axes_);
   size_t axis = axes.back();
@@ -176,20 +201,21 @@ template<typename T> py::array irfftn_internal(const py::array &in,
   auto d_out=reinterpret_cast<T *>(res.mutable_data());
   {
   py::gil_scoped_release release;
-  c2r(dims_out, s_in, s_out, axes, d_in, d_out, T(fct), nthreads);
+  T fct = norm_fct<T>(inorm, dims_out, axes);
+  c2r(dims_out, s_in, s_out, axes, d_in, d_out, fct, nthreads);
   }
   return res;
   }
 
 py::array irfftn(const py::array &in, py::object axes_, size_t lastsize,
-  double fct, size_t nthreads)
+  int inorm, size_t nthreads)
   {
-  DISPATCH(in, c128, c64, c256, irfftn_internal, (in, axes_, lastsize, fct,
+  DISPATCH(in, c128, c64, clong, irfftn_internal, (in, axes_, lastsize, inorm,
     nthreads))
   }
 
 template<typename T> py::array hartley_internal(const py::array &in,
-  py::object axes_, long double fct, bool inplace, size_t nthreads)
+  py::object axes_, int inorm, bool inplace, size_t nthreads)
   {
   auto dims(copy_shape(in));
   py::array res = inplace ? in : py::array_t<T>(dims);
@@ -200,15 +226,16 @@ template<typename T> py::array hartley_internal(const py::array &in,
   auto d_out=reinterpret_cast<T *>(res.mutable_data());
   {
   py::gil_scoped_release release;
-  r2r_hartley(dims, s_in, s_out, axes, d_in, d_out, T(fct), nthreads);
+  T fct = norm_fct<T>(inorm, dims, axes);
+  r2r_hartley(dims, s_in, s_out, axes, d_in, d_out, fct, nthreads);
   }
   return res;
   }
 
-py::array hartley(const py::array &in, py::object axes_, double fct,
+py::array hartley(const py::array &in, py::object axes_, int inorm,
   bool inplace, size_t nthreads)
   {
-  DISPATCH(in, f64, f32, f128, hartley_internal, (in, axes_, fct, inplace,
+  DISPATCH(in, f64, f32, flong, hartley_internal, (in, axes_, inorm, inplace,
     nthreads))
   }
 
@@ -261,13 +288,13 @@ template<typename T>py::array complex2hartley(const py::array &in,
 py::array mycomplex2hartley(const py::array &in,
   const py::array &tmp, py::object axes_, bool inplace)
   {
-  DISPATCH(in, f64, f32, f128, complex2hartley, (in, tmp, axes_, inplace))
+  DISPATCH(in, f64, f32, flong, complex2hartley, (in, tmp, axes_, inplace))
   }
 
-py::array hartley2(const py::array &in, py::object axes_, double fct,
+py::array hartley2(const py::array &in, py::object axes_, int inorm,
   bool inplace, size_t nthreads)
   {
-  return mycomplex2hartley(in, rfftn(in, axes_, fct, nthreads), axes_,
+  return mycomplex2hartley(in, rfftn(in, axes_, inorm, nthreads), axes_,
     inplace);
   }
 
@@ -293,8 +320,12 @@ a : numpy.ndarray (np.complex64 or np.complex128)
 axes : list of integers
     The axes along which the FFT is carried out.
     If not set, all axes will be transformed.
-fct : float
-    Normalization factor
+inorm : int
+    Normalization type
+      0 : no normalization
+      1 : divide by sqrt(N)
+      2 : divide by N
+    where N is the product of the lengths of the transformed axes.
 inplace : bool
     if False, returns the result in a new array and leaves the input unchanged.
     if True, stores the result in the input array and returns a handle to it.
@@ -317,8 +348,12 @@ a : numpy.ndarray (np.complex64 or np.complex128)
 axes : list of integers
     The axes along which the FFT is carried out.
     If not set, all axes will be transformed.
-fct : float
-    Normalization factor
+inorm : int
+    Normalization type
+      0 : no normalization
+      1 : divide by sqrt(N)
+      2 : divide by N
+    where N is the product of the lengths of the transformed axes.
 inplace : bool
     if False, returns the result in a new array and leaves the input unchanged.
     if True, stores the result in the input array and returns a handle to it.
@@ -341,8 +376,12 @@ a : numpy.ndarray (np.float32 or np.float64)
 axes : list of integers
     The axes along which the FFT is carried out.
     If not set, all axes will be transformed in ascending order.
-fct : float
-    Normalization factor
+inorm : int
+    Normalization type
+      0 : no normalization
+      1 : divide by sqrt(N)
+      2 : divide by N
+    where N is the product of the lengths of the transformed input axes.
 nthreads : int
     Number of threads to use. If 0, use the system default (typically governed
     by the `OMP_NUM_THREADS` environment variable).
@@ -363,8 +402,12 @@ a : numpy.ndarray (np.float32 or np.float64)
     The input data
 axis : int
     The axis along which the FFT is carried out.
-fct : float
-    Normalization factor
+inorm : int
+    Normalization type
+      0 : no normalization
+      1 : divide by sqrt(N)
+      2 : divide by N
+    where N is the length of `axis`.
 inplace : bool
     if False, returns the result in a new array and leaves the input unchanged.
     if True, stores the result in the input array and returns a handle to it.
@@ -391,8 +434,12 @@ axes : list of integers
     If not set, all axes will be transformed in ascending order.
 lastsize : the output size of the last axis to be transformed.
     If the corresponding input axis has size n, this can be 2*n-2 or 2*n-1.
-fct : float
-    Normalization factor
+inorm : int
+    Normalization type
+      0 : no normalization
+      1 : divide by sqrt(N)
+      2 : divide by N
+    where N is the product of the lengths of the transformed output axes.
 nthreads : int
     Number of threads to use. If 0, use the system default (typically governed
     by the `OMP_NUM_THREADS` environment variable).
@@ -414,8 +461,12 @@ a : numpy.ndarray (np.float32 or np.float64)
     FFTPACK half-complex order, i.e. `a[0].re, a[1].re, a[1].im, a[2].re ...`.
 axis : int
     The axis along which the FFT is carried out.
-fct : float
-    Normalization factor
+inorm : int
+    Normalization type
+      0 : no normalization
+      1 : divide by sqrt(N)
+      2 : divide by N
+    where N is the length of `axis`.
 inplace : bool
     if False, returns the result in a new array and leaves the input unchanged.
     if True, stores the result in the input array and returns a handle to it.
@@ -441,8 +492,12 @@ a : numpy.ndarray (np.float32 or np.float64)
 axes : list of integers
     The axes along which the transform is carried out.
     If not set, all axes will be transformed.
-fct : float
-    Normalization factor
+inorm : int
+    Normalization type
+      0 : no normalization
+      1 : divide by sqrt(N)
+      2 : divide by N
+    where N is the product of the lengths of the transformed axes.
 inplace : bool
     if False, returns the result in a new array and leaves the input unchanged.
     if True, stores the result in the input array and returns a handle to it.
@@ -463,21 +518,21 @@ PYBIND11_MODULE(pypocketfft, m)
   using namespace pybind11::literals;
 
   m.doc() = pypocketfft_DS;
-  m.def("fftn",&fftn, fftn_DS, "a"_a, "axes"_a=py::none(), "fct"_a=1.,
+  m.def("fftn",&fftn, fftn_DS, "a"_a, "axes"_a=py::none(), "inorm"_a=0,
     "inplace"_a=false, "nthreads"_a=1);
-  m.def("ifftn",&ifftn, ifftn_DS, "a"_a, "axes"_a=py::none(), "fct"_a=1.,
+  m.def("ifftn",&ifftn, ifftn_DS, "a"_a, "axes"_a=py::none(), "inorm"_a=0,
     "inplace"_a=false, "nthreads"_a=1);
-  m.def("rfftn",&rfftn, rfftn_DS, "a"_a, "axes"_a=py::none(), "fct"_a=1.,
+  m.def("rfftn",&rfftn, rfftn_DS, "a"_a, "axes"_a=py::none(), "inorm"_a=0,
     "nthreads"_a=1);
-  m.def("rfft_scipy",&rfft_scipy, rfft_scipy_DS, "a"_a, "axis"_a, "fct"_a=1.,
+  m.def("rfft_scipy",&rfft_scipy, rfft_scipy_DS, "a"_a, "axis"_a, "inorm"_a=0,
     "inplace"_a=false, "nthreads"_a=1);
   m.def("irfftn",&irfftn, irfftn_DS, "a"_a, "axes"_a=py::none(), "lastsize"_a=0,
-    "fct"_a=1., "nthreads"_a=1);
-  m.def("irfft_scipy",&irfft_scipy, irfft_scipy_DS, "a"_a, "axis"_a, "fct"_a=1.,
-    "inplace"_a=false, "nthreads"_a=1);
-  m.def("hartley",&hartley, hartley_DS, "a"_a, "axes"_a=py::none(), "fct"_a=1.,
+    "inorm"_a=0, "nthreads"_a=1);
+  m.def("irfft_scipy",&irfft_scipy, irfft_scipy_DS, "a"_a, "axis"_a,
+    "inorm"_a=0, "inplace"_a=false, "nthreads"_a=1);
+  m.def("hartley",&hartley, hartley_DS, "a"_a, "axes"_a=py::none(), "inorm"_a=0,
     "inplace"_a=false, "nthreads"_a=1);
-  m.def("hartley2",&hartley2, "a"_a, "axes"_a=py::none(), "fct"_a=1.,
+  m.def("hartley2",&hartley2, "a"_a, "axes"_a=py::none(), "inorm"_a=0,
     "inplace"_a=false, "nthreads"_a=1);
   m.def("complex2hartley",&mycomplex2hartley, "in"_a, "tmp"_a, "axes"_a,
     "inplace"_a=false);
diff --git a/stress.py b/stress.py
index 422c4a45ba1265af42e9e335ae07b563049c11cc..66644c31aa36a39f4e9973b9cd5199ca83976955 100644
--- a/stress.py
+++ b/stress.py
@@ -21,34 +21,33 @@ def test():
     nax = np.random.randint(1,ndim+1)
     axes = axes[:nax]
     lastsize = shape[axes[-1]]
-    fct = 1./np.prod(np.take(shape, axes))
     a=np.random.rand(*shape)-0.5 + 1j*np.random.rand(*shape)-0.5j
-    b=pypocketfft.ifftn(pypocketfft.fftn(a,axes=axes,nthreads=nthreads),axes=axes,fct=fct,nthreads=nthreads)
+    b=pypocketfft.ifftn(pypocketfft.fftn(a,axes=axes,nthreads=nthreads),axes=axes,inorm=2,nthreads=nthreads)
     err = _l2error(a,b)
     if err > cmaxerr:
         cmaxerr = err
         print("cmaxerr:", cmaxerr, shape, axes)
-    b=pypocketfft.irfftn(pypocketfft.rfftn(a.real,axes=axes,nthreads=nthreads),axes=axes,fct=fct,lastsize=lastsize,nthreads=nthreads)
+    b=pypocketfft.irfftn(pypocketfft.rfftn(a.real,axes=axes,nthreads=nthreads),axes=axes,inorm=2,lastsize=lastsize,nthreads=nthreads)
     err = _l2error(a.real,b)
     if err > fmaxerr:
         fmaxerr = err
         print("fmaxerr:", fmaxerr, shape, axes)
-    b=pypocketfft.ifftn(pypocketfft.fftn(a.astype(np.complex64),axes=axes,nthreads=nthreads),axes=axes,fct=fct,nthreads=nthreads)
+    b=pypocketfft.ifftn(pypocketfft.fftn(a.astype(np.complex64),axes=axes,nthreads=nthreads),axes=axes,inorm=2,nthreads=nthreads)
     err = _l2error(a.astype(np.complex64),b)
     if err > cmaxerrf:
         cmaxerrf = err
         print("cmaxerrf:", cmaxerrf, shape, axes)
-    b=pypocketfft.irfftn(pypocketfft.rfftn(a.real.astype(np.float32),axes=axes,nthreads=nthreads),axes=axes,fct=fct,lastsize=lastsize,nthreads=nthreads)
+    b=pypocketfft.irfftn(pypocketfft.rfftn(a.real.astype(np.float32),axes=axes,nthreads=nthreads),axes=axes,inorm=2,lastsize=lastsize,nthreads=nthreads)
     err = _l2error(a.real.astype(np.float32),b)
     if err > fmaxerrf:
         fmaxerrf = err
         print("fmaxerrf:", fmaxerrf, shape, axes)
-    b=pypocketfft.hartley(pypocketfft.hartley(a.real,axes=axes,nthreads=nthreads),axes=axes,fct=fct,nthreads=nthreads)
+    b=pypocketfft.hartley(pypocketfft.hartley(a.real,axes=axes,nthreads=nthreads),axes=axes,inorm=2,nthreads=nthreads)
     err = _l2error(a.real,b)
     if err > hmaxerr:
         hmaxerr = err
         print("hmaxerr:", hmaxerr, shape, axes)
-    b=pypocketfft.hartley(pypocketfft.hartley(a.real.astype(np.float32),axes=axes,nthreads=nthreads),axes=axes,fct=fct,nthreads=nthreads)
+    b=pypocketfft.hartley(pypocketfft.hartley(a.real.astype(np.float32),axes=axes,nthreads=nthreads),axes=axes,inorm=2,nthreads=nthreads)
     err = _l2error(a.real.astype(np.float32),b)
     if err > hmaxerrf:
         hmaxerrf = err
diff --git a/test.py b/test.py
index 080756d80aa6e1115e4c1e693b296ed743c8f559..d0f547cabea8737e98b6554243a0d902a74fee36 100644
--- a/test.py
+++ b/test.py
@@ -2,6 +2,7 @@ import pypocketfft
 import pyfftw
 import numpy as np
 import pytest
+from numpy.testing import assert_
 
 pmp = pytest.mark.parametrize
 
@@ -15,69 +16,70 @@ def _l2error(a,b):
     return np.sqrt(np.sum(np.abs(a-b)**2)/np.sum(np.abs(a)**2))
 
 @pmp("len", len1D)
-def test1D(len):
+@pmp("inorm", [0,1,2])
+def test1D(len, inorm):
     a=np.random.rand(len)-0.5 + 1j*np.random.rand(len)-0.5j
     b=a.astype(np.complex64)
     c=a.astype(np.complex256)
-    assert(_l2error(a, pypocketfft.ifftn(pypocketfft.fftn(c))*np.float128(1.)/len)<1e-18)
-    assert(_l2error(a, pypocketfft.ifftn(pypocketfft.fftn(a),fct=1./len))<1.5e-15)
-    assert(_l2error(a.real, pypocketfft.irfftn(pypocketfft.rfftn(a.real),fct=1./len,lastsize=len))<1.5e-15)
+    assert_(_l2error(a, pypocketfft.ifftn(pypocketfft.fftn(c,inorm=inorm), inorm=2-inorm))<1e-18)
+    assert_(_l2error(a, pypocketfft.ifftn(pypocketfft.fftn(a,inorm=inorm), inorm=2-inorm))<1.5e-15)
+    assert_(_l2error(a.real, pypocketfft.irfftn(pypocketfft.rfftn(a.real,inorm=inorm), inorm=2-inorm,lastsize=len))<1.5e-15)
     tmp=a.copy()
-    assert (pypocketfft.ifftn(pypocketfft.fftn(tmp, inplace=True), fct=1./len, inplace=True) is tmp)
-    assert(_l2error(tmp, a)<1.5e-15)
-    assert(_l2error(b, pypocketfft.ifftn(pypocketfft.fftn(b),fct=1./len))<6e-7)
-    assert(_l2error(b.real, pypocketfft.irfftn(pypocketfft.rfftn(b.real),fct=1./len,lastsize=len))<6e-7)
+    assert_ (pypocketfft.ifftn(pypocketfft.fftn(tmp, inplace=True, inorm=inorm), inplace=True, inorm=2-inorm) is tmp)
+    assert_(_l2error(tmp, a)<1.5e-15)
+    assert_(_l2error(b, pypocketfft.ifftn(pypocketfft.fftn(b, inorm=inorm), inorm=2-inorm))<6e-7)
+    assert_(_l2error(b.real, pypocketfft.irfftn(pypocketfft.rfftn(b.real, inorm=inorm), lastsize=len, inorm=2-inorm))<6e-7)
     tmp=b.copy()
-    assert (pypocketfft.ifftn(pypocketfft.fftn(tmp, inplace=True), fct=1./len, inplace=True) is tmp)
-    assert(_l2error(tmp, b)<6e-7)
+    assert_ (pypocketfft.ifftn(pypocketfft.fftn(tmp, inplace=True, inorm=inorm), inplace=True, inorm=2-inorm) is tmp)
+    assert_(_l2error(tmp, b)<6e-7)
 
 @pmp("shp", shapes)
 @pmp("nthreads", (0,1,2))
 def test_fftn(shp, nthreads):
     a=np.random.rand(*shp)-0.5 + 1j*np.random.rand(*shp)-0.5j
-    assert(_l2error(pyfftw.interfaces.numpy_fft.fftn(a), pypocketfft.fftn(a, nthreads=nthreads))<1e-15)
+    assert_(_l2error(pyfftw.interfaces.numpy_fft.fftn(a), pypocketfft.fftn(a, nthreads=nthreads))<1e-15)
     a=a.astype(np.complex64)
-    assert(_l2error(pyfftw.interfaces.numpy_fft.fftn(a), pypocketfft.fftn(a, nthreads=nthreads))<5e-7)
+    assert_(_l2error(pyfftw.interfaces.numpy_fft.fftn(a), pypocketfft.fftn(a, nthreads=nthreads))<5e-7)
 
 @pmp("shp", shapes2D)
 @pmp("axes", ((0,),(1,),(0,1),(1,0)))
 def test_fftn2D(shp, axes):
     a=np.random.rand(*shp)-0.5 + 1j*np.random.rand(*shp)-0.5j
-    assert(_l2error(pyfftw.interfaces.numpy_fft.fftn(a, axes=axes), pypocketfft.fftn(a, axes=axes))<1e-15)
+    assert_(_l2error(pyfftw.interfaces.numpy_fft.fftn(a, axes=axes), pypocketfft.fftn(a, axes=axes))<1e-15)
     a=a.astype(np.complex64)
-    assert(_l2error(pyfftw.interfaces.numpy_fft.fftn(a, axes=axes), pypocketfft.fftn(a, axes=axes))<5e-7)
+    assert_(_l2error(pyfftw.interfaces.numpy_fft.fftn(a, axes=axes), pypocketfft.fftn(a, axes=axes))<5e-7)
 
 @pmp("shp", shapes)
 def test_rfftn(shp):
     a=np.random.rand(*shp)-0.5
-    assert(_l2error(pyfftw.interfaces.numpy_fft.rfftn(a), pypocketfft.rfftn(a))<1e-15)
+    assert_(_l2error(pyfftw.interfaces.numpy_fft.rfftn(a), pypocketfft.rfftn(a))<1e-15)
     a=a.astype(np.float32)
-    assert(_l2error(pyfftw.interfaces.numpy_fft.rfftn(a), pypocketfft.rfftn(a))<5e-7)
+    assert_(_l2error(pyfftw.interfaces.numpy_fft.rfftn(a), pypocketfft.rfftn(a))<5e-7)
 
 @pmp("shp", shapes)
 def test_rfft_scipy(shp):
     for i in range(len(shp)):
         a=np.random.rand(*shp)-0.5
-        assert(_l2error(pyfftw.interfaces.scipy_fftpack.rfft(a,axis=i), pypocketfft.rfft_scipy(a,axis=i))<1e-15)
-        assert(_l2error(pyfftw.interfaces.scipy_fftpack.irfft(a,axis=i), pypocketfft.irfft_scipy(a,axis=i,fct=1./a.shape[i]))<1e-15)
+        assert_(_l2error(pyfftw.interfaces.scipy_fftpack.rfft(a,axis=i), pypocketfft.rfft_scipy(a,axis=i))<1e-15)
+        assert_(_l2error(pyfftw.interfaces.scipy_fftpack.irfft(a,axis=i), pypocketfft.irfft_scipy(a,axis=i,inorm=2))<1e-15)
 
 @pmp("shp", shapes2D)
 @pmp("axes", ((0,),(1,),(0,1),(1,0)))
 def test_rfftn2D(shp, axes):
     a=np.random.rand(*shp)-0.5
-    assert(_l2error(pyfftw.interfaces.numpy_fft.rfftn(a, axes=axes), pypocketfft.rfftn(a, axes=axes))<1e-15)
+    assert_(_l2error(pyfftw.interfaces.numpy_fft.rfftn(a, axes=axes), pypocketfft.rfftn(a, axes=axes))<1e-15)
     a=a.astype(np.float32)
-    assert(_l2error(pyfftw.interfaces.numpy_fft.rfftn(a, axes=axes), pypocketfft.rfftn(a, axes=axes))<5e-7)
+    assert_(_l2error(pyfftw.interfaces.numpy_fft.rfftn(a, axes=axes), pypocketfft.rfftn(a, axes=axes))<5e-7)
 
 @pmp("shp", shapes)
 def test_identity(shp):
     a=np.random.rand(*shp)-0.5 + 1j*np.random.rand(*shp)-0.5j
-    assert(_l2error(pypocketfft.ifftn(pypocketfft.fftn(a),fct=1./a.size), a)<1.5e-15)
+    assert_(_l2error(pypocketfft.ifftn(pypocketfft.fftn(a),inorm=2), a)<1.5e-15)
     tmp=a.copy()
-    assert (pypocketfft.ifftn(pypocketfft.fftn(tmp, inplace=True), fct=1./a.size, inplace=True) is tmp)
-    assert(_l2error(tmp, a)<1.5e-15)
+    assert_ (pypocketfft.ifftn(pypocketfft.fftn(tmp, inplace=True), inorm=2, inplace=True) is tmp)
+    assert_(_l2error(tmp, a)<1.5e-15)
     a=a.astype(np.complex64)
-    assert(_l2error(pypocketfft.ifftn(pypocketfft.fftn(a),fct=1./a.size), a)<6e-7)
+    assert_(_l2error(pypocketfft.ifftn(pypocketfft.fftn(a),inorm=2), a)<6e-7)
 
 @pmp("shp", shapes)
 def test_identity_r(shp):
@@ -85,15 +87,14 @@ def test_identity_r(shp):
     b=a.astype(np.float32)
     for ax in range(a.ndim):
         n = a.shape[ax]
-        assert(_l2error(pypocketfft.irfftn(pypocketfft.rfftn(a,(ax,)),(ax,),lastsize=n,fct=1./n), a)<1e-15)
-        assert(_l2error(pypocketfft.irfftn(pypocketfft.rfftn(b,(ax,)),(ax,),lastsize=n,fct=1./n), b)<5e-7)
+        assert_(_l2error(pypocketfft.irfftn(pypocketfft.rfftn(a,(ax,)),(ax,),lastsize=n,inorm=2), a)<1e-15)
+        assert_(_l2error(pypocketfft.irfftn(pypocketfft.rfftn(b,(ax,)),(ax,),lastsize=n,inorm=2), b)<5e-7)
 
 @pmp("shp", shapes)
 def test_identity_r2(shp):
     a=np.random.rand(*shp)-0.5 + 1j*np.random.rand(*shp)-0.5j
     a=pypocketfft.rfftn(pypocketfft.irfftn(a))
-    fct = 1./pypocketfft.irfftn(a).size
-    assert(_l2error(pypocketfft.rfftn(pypocketfft.irfftn(a),fct=fct), a)<1e-15)
+    assert_(_l2error(pypocketfft.rfftn(pypocketfft.irfftn(a),inorm=2), a)<1e-15)
 
 @pmp("shp", shapes2D+shapes3D)
 def test_hartley2(shp):
@@ -101,26 +102,25 @@ def test_hartley2(shp):
     v1 = pypocketfft.hartley2(a)
     v2 = pypocketfft.fftn(a.astype(np.complex128))
     v2 = v2.real+v2.imag
-    assert(_l2error(v1, v2)<1e-15)
+    assert_(_l2error(v1, v2)<1e-15)
 
 @pmp("shp", shapes)
 def test_hartley_identity(shp):
     a=np.random.rand(*shp)-0.5
     v1 = pypocketfft.hartley(pypocketfft.hartley(a))/a.size
-    assert(_l2error(a, v1)<1e-15)
+    assert_(_l2error(a, v1)<1e-15)
 
 @pmp("shp", shapes)
 def test_hartley2_identity(shp):
     a=np.random.rand(*shp)-0.5
     v1 = pypocketfft.hartley2(pypocketfft.hartley2(a))/a.size
-    assert(_l2error(a, v1)<1e-15)
+    assert_(_l2error(a, v1)<1e-15)
     v1 = a.copy()
-    assert (pypocketfft.hartley2(pypocketfft.hartley2(v1, inplace=True), fct=1./a.size, inplace=True) is v1)
-    assert(_l2error(a, v1)<1e-15)
+    assert_ (pypocketfft.hartley2(pypocketfft.hartley2(v1, inplace=True), inorm=2, inplace=True) is v1)
+    assert_(_l2error(a, v1)<1e-15)
 
 @pmp("shp", shapes2D)
 @pmp("axes", ((0,),(1,),(0,1),(1,0)))
 def test_hartley2_2D(shp, axes):
     a=np.random.rand(*shp)-0.5
-    fct = 1./np.prod(np.take(shp,axes))
-    assert(_l2error(pypocketfft.hartley2(pypocketfft.hartley2(a, axes=axes), axes=axes, fct=fct),a)<1e-15)
+    assert_(_l2error(pypocketfft.hartley2(pypocketfft.hartley2(a, axes=axes), axes=axes, inorm=2),a)<1e-15)