FINDING INVERSE ERROR FUNCTION

In a previous blog at autarkaw.wordpress.com (August 24, 2010), we set up a nonlinear equation to find the inverse error function. In this blog, we will solve this equation. The problem is given at and we are solving Exercise 1 of the pdf file.

Contents

TOPIC

Finding inverse error function

SUMMARY

% Language : Matlab 2010a;
% Authors : Autar Kaw;
% Mfile available at
% http://numericalmethods.eng.usf.edu/blog/inverse_erf_matlab.m;
% Last Revised : August 27, 2010
% Abstract: This program shows you how to find the inverse error function
clc
clear all

INTRODUCTION

disp('ABSTRACT')
disp('   This program shows you how to')
disp('   find the inverse error function')
disp(' ')
disp('AUTHOR')
disp('   Autar K Kaw of http://autarkaw.wordpress.com')
disp(' ')
disp('MFILE SOURCE')
disp('   http://numericalmethods.eng.usf.edu/blog/inverse_erf_matlab.m')
disp('  ')
disp('PROBLEM STATEMENT')
disp('   http://numericalmethods.eng.usf.edu/blog/inverseerror.pdf')
disp('        Exercise 1')
disp(' ')
disp('LAST REVISED')
disp('   August 27, 2010')
disp(' ')

ABSTRACT
   This program shows you how to
   find the inverse error function
 
AUTHOR
   Autar K Kaw of http://autarkaw.wordpress.com
 
MFILE SOURCE
   http://numericalmethods.eng.usf.edu/blog/inverse_erf_matlab.m
  
PROBLEM STATEMENT
   http://numericalmethods.eng.usf.edu/blog/inverseerror.pdf
        Exercise 1
 
LAST REVISED
   August 27, 2010
 

INPUTS

Value of error function

erfx=0.5;

DISPLAYING INPUTS

disp('INPUTS')
fprintf(' The value of error function= %g',erfx)
disp('  ')
disp('  ')

INPUTS
 The value of error function= 0.5  
  

CODE

syms t x
inverse_erf=solve(int(2/sqrt(pi)*exp(-t^2),t,0,x)-erfx);
inverse_erf=double(inverse_erf);

DISPLAYING OUTPUTS

disp('OUTPUTS')
fprintf(' Value of inverse error function from mfile is= %g',inverse_erf)
fprintf('\n Value of inverse error function using erfinv is= %g',erfinv(erfx))
disp('  ')

OUTPUTS
 Value of inverse error function from mfile is= 0.476936
 Value of inverse error function using erfinv is= 0.476936  

Published with MATLAB® 7.10