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,