gaussian.awk


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#!/usr/bin/awk -f

### gaussian.awk
# generate a Gaussian window
# https://en.wikipedia.org/wiki/Window_function


### Gaussian
function gaussian(n) {
    # sigma <= 0.5
    sigma = 0.4
    en[n] = (n - M)/(sigma*M)
    return exp(-0.5*e[n]*e[n])
}


BEGIN {

    ARGV[1] ? N = ARGV[1] : N = 0
    ARGV[2] ? OFMT = "%." ARGV[2] "g" : OFMT = "%g"

    # window interval goes from -M to M
    M = 0.5*(N - 1)
    pi = 4*atan2(1,1)

    for (n=0; n<N; n++) {
        if (N > 1 && M > 0) {
            w[n] = gaussian(n)
            print n, w[n]/M
        }
        else {
            print n, 1.0
        }
    }

}