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from __future__ import division
import numpy as np
from . import processing
from scipy.fftpack import dct
import math
def frequency_to_mel(f):
"""converting from frequency to Mel scale.
:param f: The frequency values(or a single frequency) in Hz.
:returns: The mel scale values(or a single mel).
"""
return 1127 * np.log(1 + f / 700.)
def mel_to_frequency(mel):
"""converting from Mel scale to frequency.
:param mel: The mel scale values(or a single mel).
:returns: The frequency values(or a single frequency) in Hz.
"""
return 700 * (np.exp(mel / 1127.0) - 1)
def triangle(x, left, middle, right):
out = np.zeros(x.shape)
out[x <= left] = 0
out[x >= right] = 0
first_half = np.logical_and(left < x, x <= middle)
out[first_half] = (x[first_half] - left) / (middle - left)
second_half = np.logical_and(middle <= x, x < right)
out[second_half] = (right - x[second_half]) / (right - middle)
return out
def zero_handling(x):
"""
This function handle the issue with zero values if the are exposed to become an argument for any lof function.
:param x: The vector.
:return: The vector with zeros substituted with epsilon values.
"""
return np.where(x == 0, np.finfo(float).eps, x)
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