# condnb

## Purpose

These functions provides the condition number of various elementary functions. Their goal is to evaluate the potential numerical difficulty of evaluating numerically a function at a given point. We may use this module while testing a given function.

The toolbox is based on macros.

To get an overview of the functions in this module, use :

help condnb_overview

This module uses the apifun module.

## Features

The following is a list of the tutorial help pages :

• Condition Overview : Condition Overview
• Tutorial : A tutorial introduction to condition numbers

The following is a list of the current functions :

• condnb_condnum : Computes the empirical condition number of the function f at point x.
• condnb_perturbation : Computes the (relative) perturbation
• condnb_plotcond : Plots the condition number of a function.
• condnb_worstinput : Computes the input producing the greatest condition number

Scalar Functions

• condnb_acoscond : Computes the condition number of the acos function.
• condnb_asincond : Computes the condition number of the asin function.
• condnb_atancond : Computes the condition number of the atan function.
• condnb_coscond : Computes the condition number of the cos function.
• condnb_erfcond : Computes the condition number of the erf function.
• condnb_erfinvcond : Computes the condition number of the erfinv function.
• condnb_expcond : Computes the condition number of the exp function.
• condnb_logcond : Computes the condition number of the log function.
• condnb_powcond : Computes the condition number of the pow function.
• condnb_sincond : Computes the condition number of the sin function.
• condnb_sqrtcond : Computes the condition number of the square root function.
• condnb_tancond : Computes the condition number of the tan function.

Norms

• condnb_matrixnorm : Computes the matrix norm
• condnb_matrixnormvector : Computes the vector maximizing a given matrix norm

Multivariate Functions

• condnb_prodcond : Computes the condition number of the product function.
• condnb_sumcond : Computes the condition number of the sum function.

## ATOMS

http://atoms.scilab.org/toolboxes/condnb

## Author

• Copyright (C) Michael Baudin, 2013 - 2016
• Copyright (C) DIGITEO, Michael Baudin, 2010-2011

## Licence

This toolbox is released under the CeCILL_V2 licence :

http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt

Development Team