functions in turbulence.i -
CreatePhaseScreens
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NT CreatePhaseScreens(dimx,dimy,prefix=) Create phase screens and save them in fits files. The saved phase screens have a dimension dimx*dimy. Number of phase screens = dimx/dimy. The phase screens are normalized so that 1 pixel = 1 r0, i.e. the variance of the squared difference of the screen with itself at one pixel interval is 6.88 (rd^2). dimx = long dimension of result screens dimy = short dimension of result screens prefix = Prefix to filename. if prefix is not set, the screens are returned by not saved. Example: CreatePhaseScreens,2048,256,prefix="screen256" F.Rigaut, 2001/11/10. modify 2003 Feb 24 to add dimy (before dimy=256) and prefix | |
SEE ALSO: | generate_phase, PhaseStructFunc |
generate_phase
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NT generate_phase(size) Generate by Fourier an un-normalized 2D phase screen from the -11/3 amplitude and a randomn phase component. Only returns the real part. Beware that these screens have a effective outer scale of about half the length of the screen. F.Rigaut, 2001/11/10. | |
SEE ALSO: | CreatePhaseScreens, PhaseStructFunc |
generatePhaseWithL0
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NT generate_phase(size,l0) Generate by Fourier an un-normalized 2D phase screen from the -11/3 amplitude and a randomn phase component. Returns the real and complex parts. Uses fftVE and cosf/sinf to keep floats for RAM use consideration (the previous version of this routine was using the yorick fft, thus double complex, which limits things on my machine to 4096 screens). dim: desired dimension of the result phase screens l0: outer scale IN PIXELS F.Rigaut, 2001/11/10. | |
SEE ALSO: | CreatePhaseScreens, PhaseStructFunc |
generateVKspectrum
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func generateVKspectrum(sdim,bdim,k0) generate correct VoKarman spectrum including aliasing. | |
SEE ALSO: |
generateVKspectrum_old
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func generateVKspectrum(sdim,bdim,k0) generate correct VoKarman spectrum including aliasing. | |
SEE ALSO: |
PhaseStructFunc
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NT PhaseStructFunc(phase,npt,step,plot=) Compute (and plot) structure function along the first dimension of array. Transpose if you need to plot structure function along another dimension. The structure function is defined as: SF(j) = avg( ( phase - shift_along_dim1_by_j (phase) )^2. ) F.Rigaut, 2001/11/10. | |
SEE ALSO: | - |