log_exp.h File Reference

Logarithmic and exponenential functions - header file. More...

#include <itpp/base/help_functions.h>
#include <itpp/itexports.h>

Go to the source code of this file.

Namespaces
namespace	itpp
	itpp namespace

Functions
double	itpp::logb (double b, double x)
	Base-b logarithm.
int	itpp::pow2i (int x)
	Calculate two to the power of x (2^x); x is integer.
double	itpp::pow2 (double x)
	Calculate two to the power of x (2^x)
double	itpp::pow10 (double x)
	Calculate ten to the power of x (10^x)
double	itpp::dB (double x)
	Decibel of x (10*log10(x))
double	itpp::inv_dB (double x)
	Inverse of decibel of x.
int	itpp::int2bits (int n)
	Calculate the number of bits needed to represent an integer n.
int	itpp::levels2bits (int n)
	Calculate the number of bits needed to represent n different values (levels).
double	itpp::trunc_log (double x)
	Truncated natural logarithm function.
double	itpp::trunc_exp (double x)
	Truncated exponential function.
double	itpp::log_add (double log_a, double log_b)
	Safe substitute for log(exp(log_a) + exp(log_b))
vec	itpp::exp (const vec &x)
	Exp of the elements of a vector x.
cvec	itpp::exp (const cvec &x)
	Exp of the elements of a complex vector x.
mat	itpp::exp (const mat &m)
	Exp of the elements of a matrix m.
cmat	itpp::exp (const cmat &m)
	Exp of the elements of a complex matrix m.
vec	itpp::pow (const double x, const vec &y)
	Calculates x to the power of y (x^y)
mat	itpp::pow (const double x, const mat &y)
	Calculates x to the power of y (x^y)
vec	itpp::pow (const vec &x, const double y)
	Calculates x to the power of y (x^y)
mat	itpp::pow (const mat &x, const double y)
	Calculates x to the power of y (x^y)
vec	itpp::pow2 (const vec &x)
	Calculates two to the power of x (2^x)
mat	itpp::pow2 (const mat &x)
	Calculates two to the power of x (2^x)
vec	itpp::pow10 (const vec &x)
	Calculates ten to the power of x (10^x)
mat	itpp::pow10 (const mat &x)
	Calculates ten to the power of x (10^x)
vec	itpp::log (const vec &x)
	The natural logarithm of the elements.
mat	itpp::log (const mat &x)
	The natural logarithm of the elements.
cvec	itpp::log (const cvec &x)
	The natural logarithm of the elements.
cmat	itpp::log (const cmat &x)
	The natural logarithm of the elements.
vec	itpp::log2 (const vec &x)
	log-2 of the elements
mat	itpp::log2 (const mat &x)
	log-2 of the elements
vec	itpp::log10 (const vec &x)
	log-10 of the elements
mat	itpp::log10 (const mat &x)
	log-10 of the elements
vec	itpp::logb (double b, const vec &x)
	log-b of x
mat	itpp::logb (double b, const mat &x)
	log-b of x
vec	itpp::dB (const vec &x)
	Calculates 10*log10(x)
mat	itpp::dB (const mat &x)
	Calculates 10*log10(x)
vec	itpp::inv_dB (const vec &x)
	Calulates the inverse of dB, 10^(x/10)
mat	itpp::inv_dB (const mat &x)
	Calculates the inverse of dB, 10^(x/10)
ivec	itpp::int2bits (const ivec &v)
	Calculate the number of bits needed to represent each integer in a vector.
ivec	itpp::levels2bits (const ivec &v)
	Calculate the number of bits needed to represent a numer of levels saved in a vector.

Variables
const double	itpp::log_double_max = std::log(std::numeric_limits<double>::max())
	Constant definition to speed up trunc_log() and trunc_exp()
const double	itpp::log_double_min = std::log(std::numeric_limits<double>::min())
	Constant definition to speed up trunc_log(), trunc_exp() and log_add()

Detailed Description

Logarithmic and exponenential functions - header file.

Author

Tony Ottosson, Adam Piatyszek and Conrad Sanderson

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Copyright (C) 1995-2010 (see AUTHORS file for a list of contributors)

This file is part of IT++ - a C++ library of mathematical, signal processing, speech processing, and communications classes and functions.

IT++ 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.

IT++ 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 IT++. If not, see http://www.gnu.org/licenses/.

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Definition in file log_exp.h.