6 lines
293 B
Text
6 lines
293 B
Text
fft::{ff2::{[n e o p t k];n::#x;
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f::{p::2:#x;e::ff2(*'p);o::ff2({x@1}'p);k::-1;
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t::{k::k+1;cmul(cexp(cdiv(cmul([0 -2];(k*pi),0);n,0));x)}'o;
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(e cadd't),e csub't};
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:[n<2;x;f(x)]};
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n::#x;k::{(2^x)<n}{1+x}:~1;n#ff2({x,0}'x,&(2^k)-n)}
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