File:Normal subgroup illustration.png

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Original file(648 × 623 pixels, file size: 48 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.

Transferred from en.wikipedia to Commons by Maksim.

The original description page was here. All following user names refer to en.wikipedia.

Summary

Made by myself with Matlab

Licensing

Public domain I, the copyright holder of this work, release this work into the public domain. This applies worldwide.
In some countries this may not be legally possible; if so:
I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

Source code


function main ()

N=12; line_thickness=2.2; font_size=25; d=0.13; big_rad=10; ball_rad=0.5; ii=sqrt(-1);
red=[1, 0, 0]; green=[0, 1, 0]; blue=[0, 0, 1];
All=[red' green' blue'];

figure(1); clf; hold on; axis equal; axis off;

Theta=0:0.1:3*pi;
X=big_rad*cos(Theta);
Y=big_rad*sin(Theta);
plot(X, Y, 'linewidth', line_thickness, 'color', [0 0 0]);

for i=0:(N-1)
   z=big_rad*exp(i*ii*2*pi/N);
   place_text_smartly (z, font_size, i, d, sprintf('%d\\pi/%d', i, N/2), N);
   color_ball(real(z), imag(z), ball_rad, All(:, mod(i, 3)+1)');
end

scale=1.4;plot(scale*big_rad,  scale*big_rad)
scale=-1.4;plot(scale*big_rad,  scale*big_rad)

saveas(gcf, 'Normal_subgroup_illustration.eps', 'psc2')
saveas(gcf, 'Normal_subgroup_illustration.png')

function place_text_smartly (z, font_size, pos, d, tx, N)
 p=cos(2*pi/N)+sqrt(-1)*sin(2*pi/N);
 z = z + p^pos * d * font_size;
 shiftx=0.0003; shifty=0.03;
 x = real (z); y=imag(z);
 H=text(x+shiftx*font_size, y+shifty*font_size, tx);
 set(H, 'fontsize', font_size, 'HorizontalAlignment', 'c', 'VerticalAlignment', 'c')

 function color_ball(x, y, r, color)
    Theta=0:0.1:2*pi;
    X=r*cos(Theta)+x;
    Y=r*sin(Theta)+y;
    H=fill(X, Y, color);
    set(H, 'EdgeColor', 'none');

date/time username edit summary
13:19, 27 October 2005 en:User:Oleg Alexandrov (<span class="autocomment"><a href="/wiki/Image:Normal_subgroup_illustration.png#Source_code" title="Image:Normal subgroup illustration.png">→</a>Source code</span>)
13:10, 27 October 2005 en:User:Oleg Alexandrov (<span class="autocomment"><a href="/wiki/Image:Normal_subgroup_illustration.png#Licensing" title="Image:Normal subgroup illustration.png">→</a>Licensing -</span> source code)
12:42, 27 October 2005 en:User:Oleg Alexandrov (Made by myself with <a href="/wiki/Matlab" title="Matlab">Matlab</a>)

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Date/TimeThumbnailDimensionsUserComment
current10:30, 20 March 2006Thumbnail for version as of 10:30, 20 March 2006648 × 623 (48 KB)MaksimLa bildo estas kopiita de wikipedia:en. La originala priskribo estas: == Summary == Made by myself with Matlab == Licensing == {{PD-self}} == Source code== <pre><nowiki> function main () N=12; line_thickness=2.2; font_size=25; d=0.13; big_rad=10;

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