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@wenLiangcan

wenLiangcan/dft.py

Forked from isnowfy/dft.py
Created May 17, 2013
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# Example usage
# $ python dft.py | gnuplot
# 9
# 0 0
# 1 1
# 2 2
# 0 2
# 1 1
# -1 1
# 0 2
# -2 2
# -1 1
import math
N = int(raw_input())
f = []
for i in range(N):
(x, y) = map(float, raw_input().split())
f.append(complex(x, y))
F = []
for i in range(N):
ang = -2 * 1j * math.pi * i / N
r = 0
for j in range(N):
r += (math.e ** (ang * j)) * f[j]
F.append(r)
print "set parametric"
print "set samples", N + 1
print "x(t)=",
for i in range(N):
ang = 2 * math.pi * i / N
if i > 0:
print "+",
print F[i].real / N, "*cos(", ang, "*t)-",
print F[i].imag / N, "*sin(", ang, "*t)",
print
print "y(t)=",
for i in range(N):
ang = 2 * math.pi * i / N
if i > 0:
print "+",
print F[i].imag / N, "*cos(", ang, "*t)+",
print F[i].real / N, "*sin(", ang, "*t)",
print
print "plot [t=0:", N, "] x(t), y(t)"
print "pause 60"
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