File:Amoeba2.png
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Size of this preview: 624 × 600 pixels. Other resolutions: 250 × 240 pixels | 499 × 480 pixels | 799 × 768 pixels | 1,065 × 1,024 pixels | 1,504 × 1,446 pixels.
Original file (1,504 × 1,446 pixels, file size: 13 KB, MIME type: image/png)
This file is from Wikimedia Commons and may be used by other projects. The description on its file description page there is shown below.
Summary
Licensing
| Public domainPublic domainfalsefalse |
| This work has been released into the public domain by its author, Oleg Alexandrov. This applies worldwide. In some countries this may not be legally possible; if so: Oleg Alexandrov grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law. |
Source code

This media was created with C++ (general-purpose programming language)
Here is a listing of the source used to create this file.
Here is a listing of the source used to create this file.
#include <iostream>
#include <fstream>
#include <cmath>
#include <complex>
using namespace std;
double small = 1e-14;
double mylog (double);
int main(){
double A=-5, B=5;
int N=1000;
double h= (B-A)/(N-1);
double theta0 = 2*M_PI/(N-1.0);
ofstream mfile ("data.txt");
for (int i=0 ; i < N ; i++){
double r = exp(A+i*h);
for (int j=0 ; j < N ; j++){
double theta = j*theta0;
complex<double> z2 = polar(r, theta);
complex<double> root = sqrt(25.0*z2*z2-12.0*(z2*z2*z2+1.0));
complex<double> z11 = (-5.0*z2+root)/6.0;
complex<double> z12 = (-5.0*z2-root)/6.0;
double a1 = mylog(abs(z11));
double a2 = mylog(abs(z12));
double b = mylog(abs(z2));
mfile << a1 << ' ' << b << endl;
mfile << a2 << ' ' << b << endl;
}
}
mfile.close();
return 0;
}
double mylog (double x){
if (x< 0){
cerr << "Error in log, negative x!" << endl;
exit(0);
}
if (x < small){
return log (small);
}
return log (x);
}
Matlab code which reads the data output by the C++ code and graphs it
A=load('data.txt');
plot(A(:, 1), A(:, 2), '.');
axis equal; axis off;
axis([-4 6 -5 5])
saveas(gcf, 'amoeba2.eps', 'psc2');
Captions
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Items portrayed in this file
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28 February 2007
image/png
a3c5be123725d2e6dfb29eba46ec56cf5d615037
13,103 byte
1,446 pixel
1,504 pixel
File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 05:22, 9 March 2007 | 1,504 × 1,446 (13 KB) | wikimediacommons>Oleg Alexandrov |
File usage
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