/*
 *  gen_dirch_mix.cc	generating random vectors 
 *			from a mixture Dirichlet densities
 *  Copyright (C) 2000,2005	Kevin Karplus
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; 
 *  version 2.1 of the License.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  See http://www.gnu.org/copyleft/lesser.html for the license details,
 *  or write to the Free Software Foundation, Inc., 59 Temple Place, Suite
 *  330, Boston, MA 02111-1307 USA
 */
/* This is a source file for a random number generator
 * that generates probability vectors according to a 
 * mixture of Dirichlet distributions.
 *
 * Kevin Karplus
 * 7 Nov 2000
 *
 * The functions here are made to look as much like a C++ class as
 * is possible in ANSI C.
 */


#include "gen_dirch_mix.h"
#include <assert.h>
#include "Utilities/Random.h"

typedef gen_dirch* gen_dirch_p;


void gen_dirch_mix::initialize(
	int alphabet_size,
	int num_components,
	const double *mix,
	const double **comps)
	// alpha values are in comps[c][0..alphabet_size-1]

{   double sum=0.;
    num_comp = num_components;
    mix_coeff_cum = new double[num_components];
    comp = new gen_dirch_p[num_components];

    for (int c=0; c<num_components; c++)
    {   sum += mix[c];
       	assert (mix[c] >=0);
	mix_coeff_cum[c] = sum;
    	
	comp[c] = new gen_dirch(alphabet_size, 	comps[c]);
    }
    assert(sum>0);
    for (int c=0; c<num_components; c++)
    {	mix_coeff_cum[c] /= sum;
    }    
}


void gen_dirch_mix::initialize(
	int alphabet_size,
	int num_components,
	const float *mix,
	const float **comps)
{   double sum=0.;
    num_comp = num_components;
    mix_coeff_cum = new double[num_components];
    comp = new gen_dirch_p[num_components];

    for (int c=0; c<num_components; c++)
    {   sum += mix[c];
       	assert (mix[c] >=0);
	mix_coeff_cum[c] = sum;
    	
	comp[c] = new gen_dirch(alphabet_size, 	comps[c]);
    }
    assert(sum>0);
    for (int c=0; c<num_components; c++)
    {	mix_coeff_cum[c] /= sum;
    }    
}


// CHANGE LOG:
// Tue Jul 19 19:34:02 PDT 2005 Kevin Karplus
//	added insert <stdlib.h>
//  Wed Jul 20 16:01:20 PDT 2005 Kevin Karplus
//	converted to c++
// Thu Jul 21 08:45:01 PDT 2005 Kevin Karplus
//	No longer use awkward indexing starting at 1 for components.
// Thu Jan 26 15:33:20 PST 2006 Kevin Karplus
//	Changed (gen_dirch*) in new arrays to gen_dirch_p