import numpy as np
from aipy import dsp
import RotMeasTools as RMT
from pylab import *
import pspec
c = 0.3 #m/ns
twopi = 2.*np.pi
N = 512
fq = np.linspace(0.1,0.2,N)
L2 = RMT.better_guess_l2(fq)
Rms,W = RMT.RMTmat(fq)
plot_me = np.zeros((N,N),dtype=np.complex)
delays = np.fft.fftshift(np.fft.fftfreq(N,fq[1]-fq[0]))
wgt = dsp.gen_window(N,window='blackman-harris')
Rm0 = 5.
for i,Rm in enumerate(Rms):
QiUi = RMT.gen_rm_spec(fq,Rm+Rm0)
plot_me[:,i] = np.fft.fftshift(np.fft.ifft(QiUi*wgt))
plot_me1 = plot_me*np.conjugate(plot_me)
plot_me1 = plot_me1.real
plot_me1 /= np.max(plot_me1)
figure(0)
imshow(10.*np.log10(plot_me1),aspect='auto',interpolation='nearest',
extent=[delays[0],delays[-1],Rms[-1],Rms[0]],
vmax=0,vmin=-100)
ylabel('Rotation Measure [$m^{-2}$]')
l2, QiUsim_l2 = [], []
for i, spec in enumerate(QiUsim):
l2i, spec_l2 = RMT.rebin_nu2lam2(fq, spec)
l2.append(l2i)
QiUsim_l2.append(spec_l2)
#plot3(l2,QiUsim_l2,RMlabel,'$\lambda^2\ (m^2)$ ','Rebinned into $\lambda^2$')
RM_samp, QiUsim_rm = [], []
for i, spec in enumerate(QiUsim_l2):
QiUsim_rm.append(np.fft.fft(QiUsim_l2[i]))
RM_samp.append(np.fft.fftfreq(len(spec), l2[i][1] - l2[i][0]) * RMT.twopi)
#plot3(RM_samp,np.abs(QiUsim_rm),RMlabel,'RM $(m^{-2})$','FFTed')
#TEST THE DFT METHOD
RM_samp, W = RMT.RMTmat(fq)
for i, spec in enumerate(QiUsim):
QiUsim_rm[i] = RMT.RMT(spec, W)
plot3(RM_samp, np.abs(QiUsim_rm), RMlabel, '$RM (m^2)$ ', 'DFT')
there_and_back_again = []
fuck_ups = []
iW = RMT.iRMTmat(fq)
for i, spec in enumerate(QiUsim_rm):
there_and_back_again.append(RMT.iRMT(spec, iW))
fuck_ups.append(there_and_back_again[-1] / QiUsim[i])
plot3(fq, there_and_back_again, RMlabel, 'Frequency (GHz)', 'iDFT')
plot3(fq, np.abs(fuck_ups), RMlabel, 'Frequency (GHz)',
'Recovered / Original [amp]')
freq=fq[Nchan / 2],
d_freq=fq[1] - fq[0])
a.img.to_fits('Fq_cube_U_1:00_-30.fits',
Pcube.imag,
clobber=True,
axes=('ra--sin', 'dec--sin', 'freq'),
ra=kwds['ra'],
dec=kwds['dec'],
d_ra=kwds['d_ra'],
d_dec=kwds['d_dec'],
freq=fq[Nchan / 2],
d_freq=fq[1] - fq[0])
#Do the RM transform
print "Beginning Rotation Measure Synthesis"
RMs, W = RMT.RMTmat(fq)
RMcube = np.zeros_like(Pcube)
for i in range(Nra):
for j in range(Ndec):
RMcube[:, i, j] = RMT.RMT(Pcube[:, i, j], W)
t2 = time.time()
print "\t --- Done in %3.3f s" % (t2 - t1)
plot(RMs, RMcube[:, Nra / 2, Ndec / 2].real)
show()
print "Writing to FITS file"
a.img.to_fits('RM_cube_real_1:00_-30.fits',
RMcube.real,
clobber=True,
