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# -*- coding: utf-8 -*-
# ######### COPYRIGHT #########
# Credits
# #######
#
# Copyright(c) 2015-2025
# ----------------------
#
# * `LabEx Archimède <http://labex-archimede.univ-amu.fr/>`_
# * `Laboratoire d'Informatique Fondamentale <http://www.lif.univ-mrs.fr/>`_
# (now `Laboratoire d'Informatique et Systèmes <http://www.lis-lab.fr/>`_)
# * `Institut de Mathématiques de Marseille <http://www.i2m.univ-amu.fr/>`_
# * `Université d'Aix-Marseille <http://www.univ-amu.fr/>`_
#
# This software is a port from LTFAT 2.1.0 :
# Copyright (C) 2005-2025 Peter L. Soendergaard <peter@sonderport.dk>.
#
# Contributors
# ------------
#
# * Denis Arrivault <contact.dev_AT_lis-lab.fr>
# * Florent Jaillet <contact.dev_AT_lis-lab.fr>
#
# Description
# -----------
#
# ltfatpy is a partial Python port of the
# `Large Time/Frequency Analysis Toolbox <http://ltfat.sourceforge.net/>`_,
# a MATLAB®/Octave toolbox for working with time-frequency analysis and
# synthesis.
#
# Version
# -------
#
# * ltfatpy version = 1.1.2
# * LTFAT version = 2.1.0
#
# Licence
# -------
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# ######### COPYRIGHT #########
"""Module that computes Diagonal of Gabor frame operator
Ported from ltfat_2.1.0/gabor/gabframediag.m
.. moduleauthor:: Denis Arrivault
"""
from __future__ import print_function, division
import numpy as np
from ltfatpy.sigproc.fir2long import fir2long
from ltfatpy.gabor.dgtlength import dgtlength
def gabframediag(g, a, M, L):
"""Diagonal of Gabor frame operator
- Usage:
| ``d = gabframediag(g, a, M, L)``
- Input parameters:
:param numpy.ndarray g: Window function
:param int a: Length of time shift
:param int M: Number of channels
:param int L: Length of transform to do
- Output parameters:
:returns: Diagonal stored as a column vector
:rtype: numpy.ndarray
``gabframediag(g, a, M, L)`` computes the diagonal of the Gabor frame
operator with respect to the window **g** and parameters **a** and **M**.
The diagonal is stored a as column vector of length **L**.
The diagonal of the frame operator can for instance be used as a
preconditioner.
.. seealso:: :func:`~ltfatpy.gabor.dgt.dgt`
"""
# Verify a, M and get L
Luser = dgtlength(L, a, M)
if L != Luser:
raise ValueError(("Incorrect transform length L={0:d} specified." +
" Next valid length is L={0:d}. See the help" +
" of DGTLENGTH for the requirements.").format(L,
Luser))
# Determine the window
(g, info) = _call_gabwin(g, a, M, L)
if L < info['gl']:
raise ValueError('Window is too long.')
# compute the diagonal
glong2 = np.abs(fir2long(g, L))**2
N = L//a
# The diagonal is a-periodic, so compute a single period by summing up
# glong2 in slices.
d = np.tile(np.sum(glong2.reshape(N, a), axis=0), (N,)) * M
return d
def _call_gabwin(g, a, M, L):
""" Internal use only """
from ltfatpy.gabor.gabwin import gabwin
return gabwin(g, a, M, L)
|
