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[edit] Source code
% illustration of tangent bundle
function main()
a=0; b=2*pi; N = 100;
X=linspace(a, b, N);
Y=sin(X); % the function to plot
XT = 0*X+1;
YT = cos(X); % derivative
Theta = linspace(a, b, N);
X = cos(Theta); Y = sin(Theta);
XT = -sin(Theta); YT = cos(Theta);
ll = 2.5; % length of lines perpendicular to the curve
thin_line = 2;
thick_line = 4;
% will draw lines tangent to the graph of Y=f(X) at
% points separted by length of 'spacing'
spacing = 0.04;
M = floor(spacing*N);
% colors
red=[0.867 0.06 0.14];
blue = [0, 129, 205]/256;
green = [0, 200, 70]/256;
gray=0.8*[1, 1, 1];
figure(1); clf; hold on; axis equal; axis off;
figure(2); clf; hold on; axis equal; axis off; view(18, 36);
% plot the curve
figure(1); s=0.95; plot (s*X, s*Y, 'linewidth', thick_line, 'color', blue);
figure(2); plot3(X, Y, 0*X, 'linewidth', thick_line, 'color', blue);
% plot the lines
for k=1:N
p = (k-1)*M+2;
if p >= N
break;
end
figure(1);
x0 = X(p); y0=Y(p); mx = XT(p); my = YT(p);
plot([x0-mx*ll, x0+mx*ll], [y0-my*ll, y0+my*ll], 'color', red, 'linewidth', thin_line)
figure(2);
plot3([X(p), X(p)], [Y(p), Y(p)], [-ll, ll], 'color', red, 'linewidth', thin_line)
end
% save to disk as eps and svg
figure(1); saveas(gcf, 'Tangent_bundle1.eps', 'psc2'); plot2svg('Tangent_bundle1.svg')
figure(2); saveas(gcf, 'Tangent_bundle2.eps', 'psc2'); plot2svg('Tangent_bundle2.svg')
File history
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| Date/Time | Dimensions | User | Comment |
current | 04:08, 12 June 2007 | 400×963 (23 KB) | Oleg Alexandrov | |
| 04:06, 12 June 2007 | 200×200 (23 KB) | Oleg Alexandrov | |
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