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37 lines
879 B
C
37 lines
879 B
C
/*
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Copyright (C) 2016 Pascal Molin
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This file is part of Arb.
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Arb is free software: you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "dirichlet.h"
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ulong
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dirichlet_group_num_primitive(const dirichlet_group_t G)
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{
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if (G->q % 4 == 2)
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return 0;
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else
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{
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slong k;
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ulong n = 1;
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/* no overflow since result < G->q */
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for (k = (G->neven == 2); k < G->num; k++)
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{
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ulong p = G->P[k].p, e = G->P[k].e;
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if (e == 1)
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n *= p - 2;
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else
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n *= (p * (p - 2) + 1) * n_pow(p, e - 2);
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}
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return n;
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}
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}
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