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31 lines
536 B
Plaintext
31 lines
536 B
Plaintext
/*
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* Copyright (c) 1995 David I. Bell
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* Permission is granted to use, distribute, or modify this source,
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* provided that this copyright notice remains intact.
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*
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* Factor using Pollard's p-1 method.
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*/
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define pfactor(N, B, ai, af)
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{
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local a, k, i, d;
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if (isnull(B))
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B = 1000;
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if (isnull(ai))
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ai = 2;
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if (isnull(af))
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af = ai + 20;
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k = lcmfact(B);
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d = lfactor(N, B);
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if (d > 1)
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return d;
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for (a = ai; a <= af; a++) {
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i = pmod(a, k, N);
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d = gcd(i - 1, N);
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if ((d > 1) && (d != N))
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return d;
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}
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return 1;
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}
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