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from math import *
def plot_elastica(a, c):
s = 500
cmd = 'moveto'
dx = .001
x, y = 0, 0
if c * c > 2 * a * a:
g = sqrt(c * c - 2 * a * a)
x = g + .01
if c == 0:
x = .001
try:
for i in range(1000):
print 6 + s * x, 200 + s * y, cmd
cmd = 'lineto'
x += dx
if 1 and c * c > 2 * a * a:
print (c * c - x * x) * (x * x - g * g)
dy = dx * (x * x - .5 * c * c - .5 * g * g) / sqrt((c * c - x * x) * (x * x - g * g))
else:
dy = dx * (a * a - c * c + x * x)/sqrt((c * c - x * x) * (2 * a * a - c * c + x * x))
y += dy
except ValueError, e:
pass
print 'stroke'
plot_elastica(1, 0)
print 'showpage'
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