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Initial data commit

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Ingy döt Net 2023-07-01 11:58:00 -04:00
parent 72d218235f
commit f23f22d71c
199087 changed files with 3378941 additions and 0 deletions
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5
Task/Fast-Fourier-transform/D/fast-fourier-transform-1.d Normal file
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void main() {
import std.stdio, std.numeric;
[1.0, 1, 1, 1, 0, 0, 0, 0].fft.writeln;
}

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Task/Fast-Fourier-transform/D/fast-fourier-transform-2.d Normal file
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import std.stdio, std.algorithm, std.range, std.math;
const(creal)[] fft(in creal[] x) pure /*nothrow*/ @safe {
immutable N = x.length;
if (N <= 1) return x;
const ev = x.stride(2).array.fft;
const od = x[1 .. $].stride(2).array.fft;
auto l = iota(N / 2).map!(k => ev[k] + expi(-2*PI * k/N) * od[k]);
auto r = iota(N / 2).map!(k => ev[k] - expi(-2*PI * k/N) * od[k]);
return l.chain(r).array;
}
void main() @safe {
[1.0L+0i, 1, 1, 1, 0, 0, 0, 0].fft.writeln;
}

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Task/Fast-Fourier-transform/D/fast-fourier-transform-3.d Normal file
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import std.stdio, std.algorithm, std.range, std.math, std.complex;
auto fft(T)(in T[] x) pure /*nothrow @safe*/ {
immutable N = x.length;
if (N <= 1) return x;
const ev = x.stride(2).array.fft;
const od = x[1 .. $].stride(2).array.fft;
alias E = std.complex.expi;
auto l = iota(N / 2).map!(k => ev[k] + T(E(-2* PI * k/N)) * od[k]);
auto r = iota(N / 2).map!(k => ev[k] - T(E(-2* PI * k/N)) * od[k]);
return l.chain(r).array;
}
void main() {
[1.0, 1, 1, 1, 0, 0, 0, 0].map!complex.array.fft.writeln;
}