A fast and precise DFT wavelet code

Vibration input parameters

A fast and precise DFT wavelet code
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This is to be used with the vibration calculation program frequencies.

The ’input.freq’ file

There are three parameters:

  • Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \mathbf{\alpha_{freq}}

to determine the step for frequency step (i.e. Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \alpha_{freq}\times

hx, Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \alpha_{freq}\times
hy, Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \alpha_{freq}\times
hz);
  • Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \mathbf{n_{freq}}

which determines the order of the finite difference scheme:

    • -1 calculates Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \frac{f(x_0)-f(x_0-h)}{h}
    • 1 calculates Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \frac{f(x_0+h)-f(x_0)}{h}
    • 2 calculates Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \frac{f(x_0+h)-f(x_0-h)}{2h}
(this is the default);
    • 3 calculates Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \frac{f(x_0+2h)+f(x_0+h)-f(x_0-h)-f(x_0-2h)}{6h}

.

  • Failed to parse (PNG conversion failed; check for correct installation of latex and dvipng (or dvips + gs + convert)): \mathbf{m_{freq}}

which determines the method (only 1 at the present stage).

Example

1/64   #frequency step = alpha*hx, alpha*hy, alpha*hz
2      #order finite difference scheme (-1, 1, 2 or 3)
1      #1 - systematic moves over each atoms
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