from yafdtd.utils import fft from math import sin, cos, pi time = numpy.arange(0,20,0.01) no_module = [gaussian(t, 10, 3) for t in time] pylab.subplot(2,2,1) pylab.plot(time, no_module) cos_module = [cos(2*pi*0.5*t)*gaussian(t, 10, 3) for t in time] sin_module = [sin(2*pi*0.5*t)*gaussian(t, 10, 3) for t in time] pylab.subplot(2,2,2) pylab.plot(time, cos_module) pylab.plot(time, sin_module) pylab.subplot(2,2,3) freq, no_module_spec = fft(time, no_module, 0.01) pylab.plot(freq[990:1010], no_module_spec[990:1010]) pylab.subplot(2,2,4) freq, cos_module_spec = fft(time, cos_module, 0.01) freq, sin_module_spec = fft(time, sin_module, 0.01) pylab.plot(freq[980:1020], cos_module_spec[980:1020]) pylab.plot(freq[980:1020], sin_module_spec[980:1020]) pylab.show()
dx = 10**-9 dt = dx/(2*c) freq = c/200e-9 print freq pylab.subplot(2,1,1) time = numpy.arange(20001) g = [cos(2*pi*freq*t*dt) for t in time] pylab.plot(time, g) g = [gaussian(t*dt, center*dt, width*dt) for t in time] # timing dt isn't necessary due to perfect scaling pylab.plot(time, g) g = [cos(2*pi*freq*t*dt)*gaussian(t*dt, center*dt, width*dt) for t in time] pylab.plot(time, g) pylab.subplot(2,1,2) freq, spectrum = fft(time, g, dt) pylab.plot(freq, spectrum) pylab.xlim(0,4e15) pylab.show()
sys.path.append(".")
from yafdtd.source import gaussian
from yafdtd.utils import fft
from math import pi, sin, cos
DEBUG = 0
n = numpy.float(2**10)
freq = 25
dt = 1./1024
t = numpy.arange(n)*dt
timedomain = numpy.cos(2*numpy.pi*freq*t)
f, freqdomain = fft(t, timedomain, dt)
if DEBUG:
for item in zip(f,freqdomain.round()):
print item
pylab.subplot(2,2,1)
pylab.plot(t,timedomain)
pylab.xlim(0, n*dt)
pylab.subplot(2,2,3)
pylab.plot(f,freqdomain)
pylab.xlim(-n/2,n/2)
n = numpy.float(2**18)