timmerlc

          Simulate a light-curve with a general periodogram shape

          light curve simulation

         timmerlc,time,rate,nt=nt,mean=mea,sigma=sigma, $
             seed=seed,dt=dt,randomu=randomu, $
             model=model,params=params,_extra=extra

          -

          dt: time resolution of the lightcurve to be simulated
          nt: Number of bins of the simulated lightcurve (default:65536)
              Should be power of two for optimum performance (FFT...)
        mean: Mean count rate of the simulated lightcurve (default: 0.)
       sigma: Standard deviation of the lightcurve to be simulated
              (default:1.)
        seed: Seed for the random number generator (returned if not
              defined -- see IDL help for randomu function)
       model: name of a function returning the desired PSD shape
              using the calling convention of mpfitfun
      params: parameters of the model (argument to model)

        randomu: if set, the IDL random number generator is used. If
                not set, ran2 (from aitlib) procedure is used.
        single: perform computations in single precision

        time: Time array (trivial :-) )
        rate: Array of countrates of length n

        seed: see above

        There are rumors that the IDL random number generator is not
        absolutely perfect -- in fact, we have seen this in our
        simulations of deadtime noise. So the periodogram has not
        perfectly independent bins. For high precision work use one
        of the rngs implemented by Sara Benlloch, ran2_normal, and
        part of aitlib.

        Simulation of the fourier transform of the light curve, and
        inverse Fourier transform. See
        J. Timmer & M. Koenig, On generating power law noise, A&A,
        300, 707-710, 1995
        for details
        RAN2_NORMAL (aitlib)

        rndpwrlc,ti,lc,mean=80.,sigma=10.,seed=seed
        psd,ti,lc,freq,psd
        plot,freq,psd,/xlog,/ylog

        Based on code by M. Koenig and J. Timmer, dated 1996 April 17
        Based on Version 1.3 of rndpwrlc by S. Benlloch, IAAT,
             dated 2002 January
        -- start of code development of code timmerlc
        New version 2002 July-September: cleaned earlier code, now
        any PSD shape is in principle possible.
 $Log: timmerlc.pro,v $
 Revision 1.2  2004/06/13 18:56:18  wilms
 made more memory efficient
 Revision 1.1  2002/09/12 08:17:45  wilms
 initial release into aitlib

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