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/*
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/*
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 *  Mathlib : A C Library of Special Functions
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 *  Mathlib : A C Library of Special Functions
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 *  Copyright (C) 1998 Ross Ihaka
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 *  Copyright (C) 1998 Ross Ihaka
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 *  Copyright (C) 2000 The R Development Core Team
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 *
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 *
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 *  This program is free software; you can redistribute it and/or modify
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 *  This program is free software; you can redistribute it and/or modify
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 *  it under the terms of the GNU General Public License as published by
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 *  it under the terms of the GNU General Public License as published by
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 *  the Free Software Foundation; either version 2 of the License, or
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 *  the Free Software Foundation; either version 2 of the License, or
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 *  (at your option) any later version.
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 *  (at your option) any later version.
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 *
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 *
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 *  You should have received a copy of the GNU General Public License
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 *  You should have received a copy of the GNU General Public License
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 *  along with this program; if not, write to the Free Software
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 *  along with this program; if not, write to the Free Software
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 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA.
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 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA.
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 *
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 *
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 *  SYNOPSIS
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 *
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 *    #include "Mathlib.h"
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 *    double dhyper(double x, double NR, double NB, double n);
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 *
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 *  DESCRIPTION
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 *  DESCRIPTION
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 *
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 *
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 *    The density of the hypergeometric distribution.
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 *    The density of the hypergeometric distribution.
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 */
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 */
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#include "Mathlib.h"
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#include "Mathlib.h"
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double dhyper(double x, double NR, double NB, double n)
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double dhyper(double x, double NR, double NB, double n, int give_log)
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{
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{
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    double N;
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    double N;
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#ifdef IEEE_754
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#ifdef IEEE_754
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    if (ISNAN(x) || ISNAN(NR) || ISNAN(NB) || ISNAN(n))
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    if (ISNAN(x) || ISNAN(NR) || ISNAN(NB) || ISNAN(n))
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	return x + NR + NB + n;
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	return x + NR + NB + n;
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    NR = floor(NR + 0.5);
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    NR = floor(NR + 0.5);
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    NB = floor(NB + 0.5);
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    NB = floor(NB + 0.5);
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    N = NR + NB;
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    N = NR + NB;
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    n = floor(n + 0.5);
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    n = floor(n + 0.5);
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    if (NR < 0 || NB < 0 || n < 0 || n > N) {
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    if (NR < 0 || NB < 0 || n < 0 || n > N) {
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	ML_ERROR(ME_DOMAIN);
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	ML_ERR_return_NAN;
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	return ML_NAN;
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    }
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    }
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    if (x < fmax2(0, n - NB) || x > fmin2(n, NR))
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    if (x < fmax2(0, n - NB) || x > fmin2(n, NR))
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	return 0;
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	return R_D__0;
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    return exp(lfastchoose(NR, x) + lfastchoose(NB, n - x)
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    return R_D_exp(lfastchoose(NR, x) + lfastchoose(NB, n - x)
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	       - lfastchoose(N, n));
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		   - lfastchoose(N, n));
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}
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}