interpolate.hh

#ifndef __SDR_INTERPOLATE_HH__
#define __SDR_INTERPOLATE_HH__

#include "buffer.hh"

namespace sdr {

static const float interpolate_taps[129][8] = {
  {  0.00000e+00,  0.00000e+00,  0.00000e+00,  0.00000e+00,  1.00000e+00,  0.00000e+00,  0.00000e+00,  0.00000e+00 },
  { -1.54700e-04,  8.53777e-04, -2.76968e-03,  7.89295e-03,  9.98534e-01, -5.41054e-03,  1.24642e-03, -1.98993e-04 },
  { -3.09412e-04,  1.70888e-03, -5.55134e-03,  1.58840e-02,  9.96891e-01, -1.07209e-02,  2.47942e-03, -3.96391e-04 },
  { -4.64053e-04,  2.56486e-03, -8.34364e-03,  2.39714e-02,  9.95074e-01, -1.59305e-02,  3.69852e-03, -5.92100e-04 },
  { -6.18544e-04,  3.42130e-03, -1.11453e-02,  3.21531e-02,  9.93082e-01, -2.10389e-02,  4.90322e-03, -7.86031e-04 },
  { -7.72802e-04,  4.27773e-03, -1.39548e-02,  4.04274e-02,  9.90917e-01, -2.60456e-02,  6.09305e-03, -9.78093e-04 },
  { -9.26747e-04,  5.13372e-03, -1.67710e-02,  4.87921e-02,  9.88580e-01, -3.09503e-02,  7.26755e-03, -1.16820e-03 },
  { -1.08030e-03,  5.98883e-03, -1.95925e-02,  5.72454e-02,  9.86071e-01, -3.57525e-02,  8.42626e-03, -1.35627e-03 },
  { -1.23337e-03,  6.84261e-03, -2.24178e-02,  6.57852e-02,  9.83392e-01, -4.04519e-02,  9.56876e-03, -1.54221e-03 },
  { -1.38589e-03,  7.69462e-03, -2.52457e-02,  7.44095e-02,  9.80543e-01, -4.50483e-02,  1.06946e-02, -1.72594e-03 },
  { -1.53777e-03,  8.54441e-03, -2.80746e-02,  8.31162e-02,  9.77526e-01, -4.95412e-02,  1.18034e-02, -1.90738e-03 },
  { -1.68894e-03,  9.39154e-03, -3.09033e-02,  9.19033e-02,  9.74342e-01, -5.39305e-02,  1.28947e-02, -2.08645e-03 },
  { -1.83931e-03,  1.02356e-02, -3.37303e-02,  1.00769e-01,  9.70992e-01, -5.82159e-02,  1.39681e-02, -2.26307e-03 },
  { -1.98880e-03,  1.10760e-02, -3.65541e-02,  1.09710e-01,  9.67477e-01, -6.23972e-02,  1.50233e-02, -2.43718e-03 },
  { -2.13733e-03,  1.19125e-02, -3.93735e-02,  1.18725e-01,  9.63798e-01, -6.64743e-02,  1.60599e-02, -2.60868e-03 },
  { -2.28483e-03,  1.27445e-02, -4.21869e-02,  1.27812e-01,  9.59958e-01, -7.04471e-02,  1.70776e-02, -2.77751e-03 },
  { -2.43121e-03,  1.35716e-02, -4.49929e-02,  1.36968e-01,  9.55956e-01, -7.43154e-02,  1.80759e-02, -2.94361e-03 },
  { -2.57640e-03,  1.43934e-02, -4.77900e-02,  1.46192e-01,  9.51795e-01, -7.80792e-02,  1.90545e-02, -3.10689e-03 },
  { -2.72032e-03,  1.52095e-02, -5.05770e-02,  1.55480e-01,  9.47477e-01, -8.17385e-02,  2.00132e-02, -3.26730e-03 },
  { -2.86289e-03,  1.60193e-02, -5.33522e-02,  1.64831e-01,  9.43001e-01, -8.52933e-02,  2.09516e-02, -3.42477e-03 },
  { -3.00403e-03,  1.68225e-02, -5.61142e-02,  1.74242e-01,  9.38371e-01, -8.87435e-02,  2.18695e-02, -3.57923e-03 },
  { -3.14367e-03,  1.76185e-02, -5.88617e-02,  1.83711e-01,  9.33586e-01, -9.20893e-02,  2.27664e-02, -3.73062e-03 },
  { -3.28174e-03,  1.84071e-02, -6.15931e-02,  1.93236e-01,  9.28650e-01, -9.53307e-02,  2.36423e-02, -3.87888e-03 },
  { -3.41815e-03,  1.91877e-02, -6.43069e-02,  2.02814e-01,  9.23564e-01, -9.84679e-02,  2.44967e-02, -4.02397e-03 },
  { -3.55283e-03,  1.99599e-02, -6.70018e-02,  2.12443e-01,  9.18329e-01, -1.01501e-01,  2.53295e-02, -4.16581e-03 },
  { -3.68570e-03,  2.07233e-02, -6.96762e-02,  2.22120e-01,  9.12947e-01, -1.04430e-01,  2.61404e-02, -4.30435e-03 },
  { -3.81671e-03,  2.14774e-02, -7.23286e-02,  2.31843e-01,  9.07420e-01, -1.07256e-01,  2.69293e-02, -4.43955e-03 },
  { -3.94576e-03,  2.22218e-02, -7.49577e-02,  2.41609e-01,  9.01749e-01, -1.09978e-01,  2.76957e-02, -4.57135e-03 },
  { -4.07279e-03,  2.29562e-02, -7.75620e-02,  2.51417e-01,  8.95936e-01, -1.12597e-01,  2.84397e-02, -4.69970e-03 },
  { -4.19774e-03,  2.36801e-02, -8.01399e-02,  2.61263e-01,  8.89984e-01, -1.15113e-01,  2.91609e-02, -4.82456e-03 },
  { -4.32052e-03,  2.43930e-02, -8.26900e-02,  2.71144e-01,  8.83893e-01, -1.17526e-01,  2.98593e-02, -4.94589e-03 },
  { -4.44107e-03,  2.50946e-02, -8.52109e-02,  2.81060e-01,  8.77666e-01, -1.19837e-01,  3.05345e-02, -5.06363e-03 },
  { -4.55932e-03,  2.57844e-02, -8.77011e-02,  2.91006e-01,  8.71305e-01, -1.22047e-01,  3.11866e-02, -5.17776e-03 },
  { -4.67520e-03,  2.64621e-02, -9.01591e-02,  3.00980e-01,  8.64812e-01, -1.24154e-01,  3.18153e-02, -5.28823e-03 },
  { -4.78866e-03,  2.71272e-02, -9.25834e-02,  3.10980e-01,  8.58189e-01, -1.26161e-01,  3.24205e-02, -5.39500e-03 },
  { -4.89961e-03,  2.77794e-02, -9.49727e-02,  3.21004e-01,  8.51437e-01, -1.28068e-01,  3.30021e-02, -5.49804e-03 },
  { -5.00800e-03,  2.84182e-02, -9.73254e-02,  3.31048e-01,  8.44559e-01, -1.29874e-01,  3.35600e-02, -5.59731e-03 },
  { -5.11376e-03,  2.90433e-02, -9.96402e-02,  3.41109e-01,  8.37557e-01, -1.31581e-01,  3.40940e-02, -5.69280e-03 },
  { -5.21683e-03,  2.96543e-02, -1.01915e-01,  3.51186e-01,  8.30432e-01, -1.33189e-01,  3.46042e-02, -5.78446e-03 },
  { -5.31716e-03,  3.02507e-02, -1.04150e-01,  3.61276e-01,  8.23188e-01, -1.34699e-01,  3.50903e-02, -5.87227e-03 },
  { -5.41467e-03,  3.08323e-02, -1.06342e-01,  3.71376e-01,  8.15826e-01, -1.36111e-01,  3.55525e-02, -5.95620e-03 },
  { -5.50931e-03,  3.13987e-02, -1.08490e-01,  3.81484e-01,  8.08348e-01, -1.37426e-01,  3.59905e-02, -6.03624e-03 },
  { -5.60103e-03,  3.19495e-02, -1.10593e-01,  3.91596e-01,  8.00757e-01, -1.38644e-01,  3.64044e-02, -6.11236e-03 },
  { -5.68976e-03,  3.24843e-02, -1.12650e-01,  4.01710e-01,  7.93055e-01, -1.39767e-01,  3.67941e-02, -6.18454e-03 },
  { -5.77544e-03,  3.30027e-02, -1.14659e-01,  4.11823e-01,  7.85244e-01, -1.40794e-01,  3.71596e-02, -6.25277e-03 },
  { -5.85804e-03,  3.35046e-02, -1.16618e-01,  4.21934e-01,  7.77327e-01, -1.41727e-01,  3.75010e-02, -6.31703e-03 },
  { -5.93749e-03,  3.39894e-02, -1.18526e-01,  4.32038e-01,  7.69305e-01, -1.42566e-01,  3.78182e-02, -6.37730e-03 },
  { -6.01374e-03,  3.44568e-02, -1.20382e-01,  4.42134e-01,  7.61181e-01, -1.43313e-01,  3.81111e-02, -6.43358e-03 },
  { -6.08674e-03,  3.49066e-02, -1.22185e-01,  4.52218e-01,  7.52958e-01, -1.43968e-01,  3.83800e-02, -6.48585e-03 },
  { -6.15644e-03,  3.53384e-02, -1.23933e-01,  4.62289e-01,  7.44637e-01, -1.44531e-01,  3.86247e-02, -6.53412e-03 },
  { -6.22280e-03,  3.57519e-02, -1.25624e-01,  4.72342e-01,  7.36222e-01, -1.45004e-01,  3.88454e-02, -6.57836e-03 },
  { -6.28577e-03,  3.61468e-02, -1.27258e-01,  4.82377e-01,  7.27714e-01, -1.45387e-01,  3.90420e-02, -6.61859e-03 },
  { -6.34530e-03,  3.65227e-02, -1.28832e-01,  4.92389e-01,  7.19116e-01, -1.45682e-01,  3.92147e-02, -6.65479e-03 },
  { -6.40135e-03,  3.68795e-02, -1.30347e-01,  5.02377e-01,  7.10431e-01, -1.45889e-01,  3.93636e-02, -6.68698e-03 },
  { -6.45388e-03,  3.72167e-02, -1.31800e-01,  5.12337e-01,  7.01661e-01, -1.46009e-01,  3.94886e-02, -6.71514e-03 },
  { -6.50285e-03,  3.75341e-02, -1.33190e-01,  5.22267e-01,  6.92808e-01, -1.46043e-01,  3.95900e-02, -6.73929e-03 },
  { -6.54823e-03,  3.78315e-02, -1.34515e-01,  5.32164e-01,  6.83875e-01, -1.45993e-01,  3.96678e-02, -6.75943e-03 },
  { -6.58996e-03,  3.81085e-02, -1.35775e-01,  5.42025e-01,  6.74865e-01, -1.45859e-01,  3.97222e-02, -6.77557e-03 },
  { -6.62802e-03,  3.83650e-02, -1.36969e-01,  5.51849e-01,  6.65779e-01, -1.45641e-01,  3.97532e-02, -6.78771e-03 },
  { -6.66238e-03,  3.86006e-02, -1.38094e-01,  5.61631e-01,  6.56621e-01, -1.45343e-01,  3.97610e-02, -6.79588e-03 },
  { -6.69300e-03,  3.88151e-02, -1.39150e-01,  5.71370e-01,  6.47394e-01, -1.44963e-01,  3.97458e-02, -6.80007e-03 },
  { -6.71985e-03,  3.90083e-02, -1.40136e-01,  5.81063e-01,  6.38099e-01, -1.44503e-01,  3.97077e-02, -6.80032e-03 },
  { -6.74291e-03,  3.91800e-02, -1.41050e-01,  5.90706e-01,  6.28739e-01, -1.43965e-01,  3.96469e-02, -6.79662e-03 },
  { -6.76214e-03,  3.93299e-02, -1.41891e-01,  6.00298e-01,  6.19318e-01, -1.43350e-01,  3.95635e-02, -6.78902e-03 },
  { -6.77751e-03,  3.94578e-02, -1.42658e-01,  6.09836e-01,  6.09836e-01, -1.42658e-01,  3.94578e-02, -6.77751e-03 },
  { -6.79662e-03,  3.96469e-02, -1.43965e-01,  6.28739e-01,  5.90706e-01, -1.41050e-01,  3.91800e-02, -6.74291e-03 },
  { -6.80032e-03,  3.97077e-02, -1.44503e-01,  6.38099e-01,  5.81063e-01, -1.40136e-01,  3.90083e-02, -6.71985e-03 },
  { -6.80007e-03,  3.97458e-02, -1.44963e-01,  6.47394e-01,  5.71370e-01, -1.39150e-01,  3.88151e-02, -6.69300e-03 },
  { -6.79588e-03,  3.97610e-02, -1.45343e-01,  6.56621e-01,  5.61631e-01, -1.38094e-01,  3.86006e-02, -6.66238e-03 },
  { -6.78771e-03,  3.97532e-02, -1.45641e-01,  6.65779e-01,  5.51849e-01, -1.36969e-01,  3.83650e-02, -6.62802e-03 },
  { -6.77557e-03,  3.97222e-02, -1.45859e-01,  6.74865e-01,  5.42025e-01, -1.35775e-01,  3.81085e-02, -6.58996e-03 },
  { -6.75943e-03,  3.96678e-02, -1.45993e-01,  6.83875e-01,  5.32164e-01, -1.34515e-01,  3.78315e-02, -6.54823e-03 },
  { -6.73929e-03,  3.95900e-02, -1.46043e-01,  6.92808e-01,  5.22267e-01, -1.33190e-01,  3.75341e-02, -6.50285e-03 },
  { -6.71514e-03,  3.94886e-02, -1.46009e-01,  7.01661e-01,  5.12337e-01, -1.31800e-01,  3.72167e-02, -6.45388e-03 },
  { -6.68698e-03,  3.93636e-02, -1.45889e-01,  7.10431e-01,  5.02377e-01, -1.30347e-01,  3.68795e-02, -6.40135e-03 },
  { -6.65479e-03,  3.92147e-02, -1.45682e-01,  7.19116e-01,  4.92389e-01, -1.28832e-01,  3.65227e-02, -6.34530e-03 },
  { -6.61859e-03,  3.90420e-02, -1.45387e-01,  7.27714e-01,  4.82377e-01, -1.27258e-01,  3.61468e-02, -6.28577e-03 },
  { -6.57836e-03,  3.88454e-02, -1.45004e-01,  7.36222e-01,  4.72342e-01, -1.25624e-01,  3.57519e-02, -6.22280e-03 },
  { -6.53412e-03,  3.86247e-02, -1.44531e-01,  7.44637e-01,  4.62289e-01, -1.23933e-01,  3.53384e-02, -6.15644e-03 },
  { -6.48585e-03,  3.83800e-02, -1.43968e-01,  7.52958e-01,  4.52218e-01, -1.22185e-01,  3.49066e-02, -6.08674e-03 },
  { -6.43358e-03,  3.81111e-02, -1.43313e-01,  7.61181e-01,  4.42134e-01, -1.20382e-01,  3.44568e-02, -6.01374e-03 },
  { -6.37730e-03,  3.78182e-02, -1.42566e-01,  7.69305e-01,  4.32038e-01, -1.18526e-01,  3.39894e-02, -5.93749e-03 },
  { -6.31703e-03,  3.75010e-02, -1.41727e-01,  7.77327e-01,  4.21934e-01, -1.16618e-01,  3.35046e-02, -5.85804e-03 },
  { -6.25277e-03,  3.71596e-02, -1.40794e-01,  7.85244e-01,  4.11823e-01, -1.14659e-01,  3.30027e-02, -5.77544e-03 },
  { -6.18454e-03,  3.67941e-02, -1.39767e-01,  7.93055e-01,  4.01710e-01, -1.12650e-01,  3.24843e-02, -5.68976e-03 },
  { -6.11236e-03,  3.64044e-02, -1.38644e-01,  8.00757e-01,  3.91596e-01, -1.10593e-01,  3.19495e-02, -5.60103e-03 },
  { -6.03624e-03,  3.59905e-02, -1.37426e-01,  8.08348e-01,  3.81484e-01, -1.08490e-01,  3.13987e-02, -5.50931e-03 },
  { -5.95620e-03,  3.55525e-02, -1.36111e-01,  8.15826e-01,  3.71376e-01, -1.06342e-01,  3.08323e-02, -5.41467e-03 },
  { -5.87227e-03,  3.50903e-02, -1.34699e-01,  8.23188e-01,  3.61276e-01, -1.04150e-01,  3.02507e-02, -5.31716e-03 },
  { -5.78446e-03,  3.46042e-02, -1.33189e-01,  8.30432e-01,  3.51186e-01, -1.01915e-01,  2.96543e-02, -5.21683e-03 },
  { -5.69280e-03,  3.40940e-02, -1.31581e-01,  8.37557e-01,  3.41109e-01, -9.96402e-02,  2.90433e-02, -5.11376e-03 },
  { -5.59731e-03,  3.35600e-02, -1.29874e-01,  8.44559e-01,  3.31048e-01, -9.73254e-02,  2.84182e-02, -5.00800e-03 },
  { -5.49804e-03,  3.30021e-02, -1.28068e-01,  8.51437e-01,  3.21004e-01, -9.49727e-02,  2.77794e-02, -4.89961e-03 },
  { -5.39500e-03,  3.24205e-02, -1.26161e-01,  8.58189e-01,  3.10980e-01, -9.25834e-02,  2.71272e-02, -4.78866e-03 },
  { -5.28823e-03,  3.18153e-02, -1.24154e-01,  8.64812e-01,  3.00980e-01, -9.01591e-02,  2.64621e-02, -4.67520e-03 },
  { -5.17776e-03,  3.11866e-02, -1.22047e-01,  8.71305e-01,  2.91006e-01, -8.77011e-02,  2.57844e-02, -4.55932e-03 },
  { -5.06363e-03,  3.05345e-02, -1.19837e-01,  8.77666e-01,  2.81060e-01, -8.52109e-02,  2.50946e-02, -4.44107e-03 },
  { -4.94589e-03,  2.98593e-02, -1.17526e-01,  8.83893e-01,  2.71144e-01, -8.26900e-02,  2.43930e-02, -4.32052e-03 },
  { -4.82456e-03,  2.91609e-02, -1.15113e-01,  8.89984e-01,  2.61263e-01, -8.01399e-02,  2.36801e-02, -4.19774e-03 },
  { -4.69970e-03,  2.84397e-02, -1.12597e-01,  8.95936e-01,  2.51417e-01, -7.75620e-02,  2.29562e-02, -4.07279e-03 },
  { -4.57135e-03,  2.76957e-02, -1.09978e-01,  9.01749e-01,  2.41609e-01, -7.49577e-02,  2.22218e-02, -3.94576e-03 },
  { -4.43955e-03,  2.69293e-02, -1.07256e-01,  9.07420e-01,  2.31843e-01, -7.23286e-02,  2.14774e-02, -3.81671e-03 },
  { -4.30435e-03,  2.61404e-02, -1.04430e-01,  9.12947e-01,  2.22120e-01, -6.96762e-02,  2.07233e-02, -3.68570e-03 },
  { -4.16581e-03,  2.53295e-02, -1.01501e-01,  9.18329e-01,  2.12443e-01, -6.70018e-02,  1.99599e-02, -3.55283e-03 },
  { -4.02397e-03,  2.44967e-02, -9.84679e-02,  9.23564e-01,  2.02814e-01, -6.43069e-02,  1.91877e-02, -3.41815e-03 },
  { -3.87888e-03,  2.36423e-02, -9.53307e-02,  9.28650e-01,  1.93236e-01, -6.15931e-02,  1.84071e-02, -3.28174e-03 },
  { -3.73062e-03,  2.27664e-02, -9.20893e-02,  9.33586e-01,  1.83711e-01, -5.88617e-02,  1.76185e-02, -3.14367e-03 },
  { -3.57923e-03,  2.18695e-02, -8.87435e-02,  9.38371e-01,  1.74242e-01, -5.61142e-02,  1.68225e-02, -3.00403e-03 },
  { -3.42477e-03,  2.09516e-02, -8.52933e-02,  9.43001e-01,  1.64831e-01, -5.33522e-02,  1.60193e-02, -2.86289e-03 },
  { -3.26730e-03,  2.00132e-02, -8.17385e-02,  9.47477e-01,  1.55480e-01, -5.05770e-02,  1.52095e-02, -2.72032e-03 },
  { -3.10689e-03,  1.90545e-02, -7.80792e-02,  9.51795e-01,  1.46192e-01, -4.77900e-02,  1.43934e-02, -2.57640e-03 },
  { -2.94361e-03,  1.80759e-02, -7.43154e-02,  9.55956e-01,  1.36968e-01, -4.49929e-02,  1.35716e-02, -2.43121e-03 },
  { -2.77751e-03,  1.70776e-02, -7.04471e-02,  9.59958e-01,  1.27812e-01, -4.21869e-02,  1.27445e-02, -2.28483e-03 },
  { -2.60868e-03,  1.60599e-02, -6.64743e-02,  9.63798e-01,  1.18725e-01, -3.93735e-02,  1.19125e-02, -2.13733e-03 },
  { -2.43718e-03,  1.50233e-02, -6.23972e-02,  9.67477e-01,  1.09710e-01, -3.65541e-02,  1.10760e-02, -1.98880e-03 },
  { -2.26307e-03,  1.39681e-02, -5.82159e-02,  9.70992e-01,  1.00769e-01, -3.37303e-02,  1.02356e-02, -1.83931e-03 },
  { -2.08645e-03,  1.28947e-02, -5.39305e-02,  9.74342e-01,  9.19033e-02, -3.09033e-02,  9.39154e-03, -1.68894e-03 },
  { -1.90738e-03,  1.18034e-02, -4.95412e-02,  9.77526e-01,  8.31162e-02, -2.80746e-02,  8.54441e-03, -1.53777e-03 },
  { -1.72594e-03,  1.06946e-02, -4.50483e-02,  9.80543e-01,  7.44095e-02, -2.52457e-02,  7.69462e-03, -1.38589e-03 },
  { -1.54221e-03,  9.56876e-03, -4.04519e-02,  9.83392e-01,  6.57852e-02, -2.24178e-02,  6.84261e-03, -1.23337e-03 },
  { -1.35627e-03,  8.42626e-03, -3.57525e-02,  9.86071e-01,  5.72454e-02, -1.95925e-02,  5.98883e-03, -1.08030e-03 },
  { -1.16820e-03,  7.26755e-03, -3.09503e-02,  9.88580e-01,  4.87921e-02, -1.67710e-02,  5.13372e-03, -9.26747e-04 },
  { -9.78093e-04,  6.09305e-03, -2.60456e-02,  9.90917e-01,  4.04274e-02, -1.39548e-02,  4.27773e-03, -7.72802e-04 },
  { -7.86031e-04,  4.90322e-03, -2.10389e-02,  9.93082e-01,  3.21531e-02, -1.11453e-02,  3.42130e-03, -6.18544e-04 },
  { -5.92100e-04,  3.69852e-03, -1.59305e-02,  9.95074e-01,  2.39714e-02, -8.34364e-03,  2.56486e-03, -4.64053e-04 },
  { -3.96391e-04,  2.47942e-03, -1.07209e-02,  9.96891e-01,  1.58840e-02, -5.55134e-03,  1.70888e-03, -3.09412e-04 },
  { -1.98993e-04,  1.24642e-03, -5.41054e-03,  9.98534e-01,  7.89295e-03, -2.76968e-03,  8.53777e-04, -1.54700e-04 },
  {  0.00000e+00,  0.00000e+00,  0.00000e+00,  1.00000e+00,  0.00000e+00,  0.00000e+00,  0.00000e+00,  0.00000e+00 },
};


template <class Scalar>
static inline Scalar interpolate(const Buffer<Scalar> &in, float mu) {
  Scalar out = 0;
  const float *filter = interpolate_taps[int(roundf(mu*128))];
  for (size_t i=0; i<8; i++) { out += in[i]*filter[i]; }
  return Scalar(out);
}

}

#endif // __SDR_INTERPOLATE_HH__