#!/usr/bin/env python3
"""verify_lut3.py — LUT-кривая с узлами в колене (x=0.574/0.61), форма B.10."""
import numpy as np
from scipy.interpolate import PchipInterpolator

FS = 44100.0
DEPTH = 0.8639736175537109
QS = [0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.0, 5.0, 10.0]
DUAL = np.array([(10.220, 15.224), (10.219, 13.963), (10.219, 12.947),
                 (10.219, 11.725), (10.218, 11.119), (10.216, 10.689),
                 (10.210, 10.412), (10.203, 10.305), (10.182, 10.225),
                 (10.113, 10.183), (9.822, 10.165)])
FCS = [800.0, 900.0, 950.0, 1000.0, 1050.0, 1100.0, 1200.0]
T1KQ = np.array([7.868, 8.536, 8.726, 8.788, 8.729, 8.575, 8.115])
T1K = np.array([14.548, 15.332, 15.553, 15.626, 15.557, 15.378, 14.840])
L_DUAL = 10 ** (-7.142 / 20)
L_T1KQ = 10 ** (-18.063 / 20)
L_T1K = 1.0
TILT = {500: 1.414, 1000: 1.454, 2000: 1.795}
Q, G = 0.900, 4.132

# узлы: (-0.75,0.4453) (-0.5,0.4551) (-0.25,0.4784) (0,0.5041) (0.25,0.5331)
#        (0.308,0.540?) (0.5,0.5715) (0.574,0.566) (0.61,0.647) (0.75,0.657) (1.0,0.664)
LUTX = np.array([-0.75, -0.50, -0.25, 0.00, 0.25, 0.50, 0.574, 0.61, 0.75, 1.00])
LUTY = np.array([0.4453, 0.4551, 0.4784, 0.5041, 0.5331, 0.5715, 0.5660, 0.6470, 0.6574, 0.6636])
lut = PchipInterpolator(LUTX, LUTY)


def res_at(ft, fc, Q, g):
    w0 = fc * 2 * np.pi / FS
    c, s = np.cos(w0), np.sin(w0)
    p = (s * 0.5) / Q
    a, a2 = p * g, p / g
    A = [a + 1, -2 * c, 1 - a]
    B = [a2 + 1, -2 * c, 1 - a2]
    w = 2 * np.pi * ft / FS
    z = np.exp(-1j * w)
    return np.abs(2.0 * (B[0] + B[1] * z + B[2] * z * z) /
                  (A[0] + A[1] * z + A[2] * z * z))


def red(x, tilt):
    C = DEPTH * tilt * lut(x)
    return -20 * np.log10(max(1 - C, 1e-9))


def run():
    preds, meas, tags = [], [], []
    for i, q in enumerate(QS):
        for f, m in ((500, DUAL[i, 0]), (2000, DUAL[i, 1])):
            p = red(np.log10(L_DUAL / res_at(f, 500, q, G)), TILT[f])
            preds.append(p); meas.append(m); tags.append(f'dual{q}@{f}')
    for i, fc in enumerate(FCS):
        r = res_at(1000, fc, 0.9999978, G)
        preds.append(red(np.log10(L_T1KQ / r), TILT[1000])); meas.append(T1KQ[i]); tags.append(f't1kq{fc}')
        preds.append(red(np.log10(L_T1K / r), TILT[1000])); meas.append(T1K[i]); tags.append(f't1k{fc}')
    preds = np.array(preds); meas = np.array(meas)
    rmse = np.sqrt(np.mean((preds - meas) ** 2))
    print(f'rmse={rmse:.4f} dB')
    for t, m, p in zip(tags, meas, preds):
        if abs(p - m) > 0.15:
            print(f'  {t:12s} {m:7.3f}/{p:7.3f}  ({p - m:+.3f})')


if __name__ == '__main__':
    run()