mole_solve.cpp

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/* This file is part of Cloudy and is copyright (C)1978-2022 by Gary J. Ferland and
 * others.  For conditions of distribution and use see copyright notice in license.txt */
/*CO_step fills in matrix for heavy elements molecular routines */
#include "cddefines.h"
#include "deuterium.h"
#include "ionbal.h"
#include "phycon.h"
#include "hmi.h"
#include "dynamics.h"
#include "conv.h"
#include "trace.h"
#include "grainvar.h"
#include "newton_step.h"
#include "h2.h"
#include "mole_priv.h"
#include "mole.h"
#include "dense.h"
/* Nick Abel between July and October of 2003 assisted Dr. Ferland in
 * improving the heavy element molecular network in Cloudy. Before
 * this routine would predict negative abundances if the fraction of
 * carbon in the form of molecules came close to 100%. A reorganizing
 * of the reaction network detected several bugs.  Treatment of
 * "coupled reactions", in which both densities in the reaction rate
 * were being predicted by Cloudy, were also added.  Due to these
 * improvements, Cloudy can now perform calculations where 100% of the
 * carbon is in the form of CO without predicting negative abundances
 *
 * Additional changes were made in November of 2003 so that our reaction 
 * network would include all reactions from the TH85 paper.  This involved 
 * adding silicon to the chemical network.  Also the reaction rates were
 * labeled to make identification with the reaction easier and the matrix 
 * elements of atomic C, O, and Si are now done in a loop, which makes 
 * the addition of future chemical species (like N or S) easy.
 * */
void check_co_ion_converge(void);

STATIC void funjac(GroupMap &MoleMap, const valarray<double> &b2vec,
                                                 double * const ervals, double * const amat, const bool lgJac, bool *lgConserve);

STATIC void mole_h_fixup(void);

STATIC void grouped_elems(const double bvec[], double mole_elems[]);

#define SMALLABUND 1e-24

double mole_solve()
{
        int nBad, nPrevBad, i;
        realnum
                eqerror, error;
        valarray<double> oldmols(mole_global.num_compacted),
                newmols(mole_global.num_compacted);
        GroupMap MoleMap( nuclide_list.size() );

        DEBUG_ENTRY( "mole_solve()" );

        if (hmi.H2_frac_abund_set>0.)
        {
                mole_h_fixup();
                fixit("Need to treat hmi.H2_frac_abund_set in revised network"); 
                fprintf(stderr,"Need to treat hmi.H2_frac_abund_set in revised network\n");
                fprintf(stderr,"%g\n",hmi.H2_frac_abund_set);
                exit(-1);
        }

        ASSERT(lgElemsConserved());

        /* will test against this error for quitting */
        const double BIGERROR = 1e-8;
        /* >>chng 04 jul 20, upper limit had been 6, why?  change to 20
         * to get closer to soln */
        const int LIM_LOOP = 100;
        /* loop until run to limit, or no fix ups needed and error is small */
        /* will be used to keep track of neg solns */
        nBad = nPrevBad = 0;
        eqerror = -1.;

        valarray<double> escale(mole_global.num_compacted);
        double rlimit=-1., rmax=0.0;
                
        // Run enough times through to converge nonlinear system.
        for(i=0; i < LIM_LOOP;i++) 
        {
                if (trace.lgTrace)
                {
                        fprintf(ioQQQ," Mole solve loop %d\n",i);
                }

                {
                        /* option to print deduced abundances */
                        /*@-redef@*/
                        enum {DEBUG_LOC=false};
                        /*@+redef@*/
                        if( DEBUG_LOC && (nzone>140) )
                        {
                                fprintf(ioQQQ,"DEBUG hmole in \t%.2f\t%.5e\t%.5e",
                                        fnzone,
                                        phycon.te,
                                        dense.eden);
                                for( long k=0; k<mole_global.num_calc; k++ )
                                        fprintf(ioQQQ,"\t%.2e", mole.species[k].den );
                                fprintf(ioQQQ,"\n" );
                        }
                }
                /* nBad returns number of times negative abundances were fixed
                 * for latest step, should be zero at return for valid soln */

                nPrevBad = nBad;

                MoleMap.setup(get_ptr(oldmols));

                long j;

                // Need to allow enough loops for j that rlimit increases until
                // no species get to -ve densities.  Often, though, this will
                // just be the first time through.
                static ConvergenceCounter cctr=conv.register_("MOLE_SOLVE");
                ++cctr;
                for (j=0; j<30; j++) 
                {
                        static ConvergenceCounter cctrs=conv.register_("MOLE_SOLVE_STEPS");
                        ++cctrs;
                        bool lgOK = newton_step(MoleMap, oldmols, newmols, &eqerror, &error, mole_global.num_compacted, &rlimit, &rmax, escale, funjac); 
                
                        /* check for negative populations */
                        if (lgOK)
                        {
                                nBad = 0; 
                                double oldMolsTmp = 0.;
                                double newMolsTmp = 0.;
                                long iworst = -1;
                                for( long mol=0; mol < mole_global.num_compacted; mol++ )
                                {
                                        if( newmols[mol] < 0. ) 
                                        {
                                                if( -newmols[mol]*oldMolsTmp >= oldmols[mol]*newMolsTmp )
                                                {
                                                        
                                                        oldMolsTmp = abs(oldmols[mol]);
                                                        newMolsTmp = abs(newmols[mol]);
                                                        iworst = mol;
                                                }
                                                if( newmols[mol] < -SMALLABUND) 
                                                {
                                                        ++nBad;
                                                }
                                                newmols[mol] = 0.;
                                        }
                                }
                                if ( 0 != nBad)
                                {
                                        lgOK = false;
                                        if (0)
                                        {
                                                fprintf(ioQQQ,"-ve density in inner chemistry loop %ld, worst is %s rlimit %g\n",j,groupspecies[iworst]->label.c_str(),rlimit);
                                        }
                                }
                        }
                        if ( lgOK )
                        {
                                //fprintf(ioQQQ,"OK at z %ld l %d j %ld t %g e %g\n",nzone,i,j,1./rlimit,eqerror);
                                break;
                        }

                        ASSERT( rlimit < BIGFLOAT );
                        ASSERT( rlimit > 0.0 );
                        rlimit = 10.*rlimit;
                }
                
                //fprintf(stdout,"Mole zone %ld -- %7.2f error %15.8g eqerror %15.8g rlimit %15.8g nBad %d ninner %ld loop %d\n",nzone,fnzone,error,eqerror,rlimit,nBad,j+1,i);

                // If the accuracy of the solution obtained was strongly limited
                // by the pseudo-timestep limit, extend it
                if ( error < 0.01*eqerror )
                        rlimit = 0.1*rlimit;
                
                MoleMap.updateMolecules( newmols );
                        
                /* Stop early if good enough */
                if (eqerror < BIGERROR && nBad == 0 && nPrevBad == 0) 
                        break;
        }

        //fprintf(stdout,"Mole: zn %ld -- %7.2f err %13.6g rlimit %13.6g nBad %d loop %d\n",nzone,fnzone,eqerror,rlimit,nBad,i);

        if( (i == LIM_LOOP && eqerror > BIGERROR)  || nBad != 0 )
        {
                conv.setConvIonizFail("Chem conv", eqerror, nBad);
        }
        
        // Effect_delta determines whether changes due to the molecular
        // network rescale values enough to invalidate other solutions
        realnum effect_delta = mole_return_cached_species(MoleMap);

        realnum delta_threshold = 0.2*conv.IonizErrorAllowed;
        if (effect_delta > delta_threshold)
        {
                conv.setConvIonizFail("chem eft chg", effect_delta, 0.0);
        }               

        if (trace.lgTrace)
        {
                fprintf(ioQQQ,"Mole zn %3ld -- %7.2f\n",nzone,fnzone); 
                fprintf(ioQQQ,"Internal error %15.8g nBad %4d loops %3d\n",
                                  eqerror,nBad,i);
                fprintf(ioQQQ,"Scaling delta on ions %15.8g; threshold %15.8g\n", 
                                  effect_delta, delta_threshold);
        }

        check_co_ion_converge();

        {
                /* option to print deduced abundances */
                /*@-redef@*/
                enum {DEBUG_LOC=false};
                /*@+redef@*/
                if( DEBUG_LOC /*&& (nzone>68)*/ )
                {
                        fprintf(ioQQQ,"DEBUG mole out\t%i\t%.2f\t%.5e\t%.5e",
                                                        i,
                                                        fnzone,
                                                        phycon.te,
                                                        dense.eden);
                        fprintf(ioQQQ,
                                                        "\terror\t%.4e\tH0\t%.4e\tH+\t%.4e\tsink\t%.4e\t%.4e\tsour\t%.4e\t%.4e\tion\t%.4e\trec\t%.4e", 
                                                        eqerror,
                                                        dense.xIonDense[ipHYDROGEN][0],
                                                        dense.xIonDense[ipHYDROGEN][1],
                                                        mole.sink[ipHYDROGEN][0],
                                                        mole.sink[ipHYDROGEN][1],
                                                        mole.source[ipHYDROGEN][0] , 
                                                        mole.source[ipHYDROGEN][1] ,
                                                        ionbal.RateIonizTot(ipHYDROGEN,0),
                                                        ionbal.RateRecomTot[ipHYDROGEN][0]);
                        
                        /*for( j=0; j<mole_global.num_calc; j++ )
                                fprintf(ioQQQ,"\t%.4e", HMOLEC(j) );*/
                        fprintf(ioQQQ,"\n" );
                }
        }
        
        return eqerror;

/*lint +e550 */
/*lint +e778 constant expression evaluates to 0 in operation '-' */
}


void check_co_ion_converge(void)
{
        DEBUG_ENTRY( "check_co_ion_converge()" );
        /* check whether ion and chem solvers agree yet */
        if( dense.lgElmtOn[ipCARBON] &&
                fabs(dense.xIonDense[ipCARBON][0]- findspecieslocal("C")->den)/SDIV(dense.gas_phase[ipCARBON]) >0.001 )
        {
                conv.setConvIonizFail("CO C0 con",
                                                                         dense.xIonDense[ipCARBON][0],
                                                                         findspecieslocal("C")->den);
        }
        else if( dense.lgElmtOn[ipCARBON] &&
                fabs(dense.xIonDense[ipCARBON][1]- findspecieslocal("C+")->den)/SDIV(dense.gas_phase[ipCARBON]) >0.001 )
        {
                conv.setConvIonizFail("CO C1 con",
                                                                         dense.xIonDense[ipCARBON][1],
                                                                         findspecieslocal("C+")->den);
        }
        else if( dense.lgElmtOn[ipOXYGEN] &&
                fabs(dense.xIonDense[ipOXYGEN][0]- findspecieslocal("O")->den)/SDIV(dense.gas_phase[ipOXYGEN]) >0.001 )
        {
                conv.setConvIonizFail(
                        "CO O0 con",dense.xIonDense[ipOXYGEN][0],
                        findspecieslocal("O")->den);
        }
        else if( dense.lgElmtOn[ipOXYGEN] &&
                fabs(dense.xIonDense[ipOXYGEN][1]- findspecieslocal("O+")->den)/SDIV(dense.gas_phase[ipOXYGEN]) >0.001 )
        {
                conv.setConvIonizFail(
                        "CO O1 con", dense.xIonDense[ipOXYGEN][1],
                        findspecieslocal("O+")->den);
        }
}

STATIC void mole_h_fixup(void)
{
        long int mol;
        
        /* there are two "no molecules" options, the no co, which turns off everything,
         * and the no n2, which only turns off the h2.  in order to not kill the co
         * part we still need to compute the hydrogen network here, and then set h2 to
         * small values */
        /* >> chng 03 jan 15 rjrw -- suddenly switching off molecules confuses the solvers... */
        DEBUG_ENTRY( "mole_h_fixup()" );

        /* >>chng 02 jun 19, add option to force H2 abundance, for testing h2 molecules,
         * hmi.H2_frac_abund_set is fraction in molecules that is set by set h2 fraction command */
        if( hmi.H2_frac_abund_set>0.)
        {
                for(mol=0;mol<mole_global.num_calc;mol++) 
                {
                        mole.species[mol].den = 0.;
                }
                /* >>chng 03 jul 19, from 0 to SMALLFLOAT, to pass asserts in ConvBase,
                 * problem is that ion range has not been reset for hydrogen */
                dense.xIonDense[ipHYDROGEN][0] = dense.xIonDense[ipHYDROGEN][1] = 
                        2.f*SMALLFLOAT*dense.gas_phase[ipHYDROGEN];
                /* put it all in the ground state */
                findspecieslocal("H2")->den = (realnum)(dense.gas_phase[ipHYDROGEN] * hmi.H2_frac_abund_set);
                findspecieslocal("H2*")->den = 0.;

                hmi.H2_total = findspecieslocal("H2")->den + findspecieslocal("H2*")->den;
                /* first guess at ortho and para densities */
                h2.ortho_density = 0.75*hmi.H2_total;
                h2.para_density = 0.25*hmi.H2_total;
                {
                        hmi.H2_total_f = (realnum)hmi.H2_total;
                        h2.ortho_density_f = (realnum)h2.ortho_density;
                        h2.para_density_f = (realnum)h2.para_density;
                }

                hmi.hmihet = 0.;
                hmi.h2plus_exc_frac = 0.;
                hmi.h2plus_heatcoef = 0.;
                hmi.h2plus_heat = 0.;
                hmi.H2Opacity = 0.;
                hmi.hmicol = 0.;
                hmi.HeatH2Dish_TH85 = 0.;
                hmi.HeatH2Dexc_TH85 = 0.;
                hmi.deriv_HeatH2Dexc_TH85 = 0.;
                hmi.hmidep = 1.;

                for( size_t nd=0; nd < gv.bin.size(); nd++ )
                {
                        gv.bin[nd]->rate_h2_form_grains_used = 0.;
                }

                return;
        }
}

#define ABSLIM  1e-12
#define ERRLIM  1e-12
#       ifdef MAT
#               undef MAT
#       endif
#       define MAT(a,I_,J_)     ((a)[(I_)*(mole_global.num_compacted)+(J_)])


STATIC void mole_eval_dynamic_balance(long int num_total, double *b, bool lgJac, multi_arr<double,2> &c);
enum {PRINTSOL = false};

STATIC void funjac(GroupMap &MoleMap, const valarray<double> &b2vec, double * const ervals,
                                                 double * const amat, const bool lgJac, bool *lgConserve)
{
        static multi_arr<double,2> c(mole_global.num_total,mole_global.num_total);
        bool printsol = PRINTSOL;
        valarray<double> b(mole_global.num_total);

        DEBUG_ENTRY( "funjac()" );

        MoleMap.updateMolecules( b2vec );               
                
        if( iteration >= dynamics.n_initial_relax+1 &&
                ( dynamics.lgAdvection || dynamics.lgTimeDependentStatic ) && 
                dynamics.Rate != 0.0) 
        {
                ASSERT(dynamics.Rate > 0.0);
                *lgConserve = false; 
        }
        else
        {
                *lgConserve = true; 
        }               

        /* Generate chemical balance vector (mole.b[]) and Jacobian array 
                 (c[][], first iteration) from reaction list */
        
        mole_eval_dynamic_balance(mole_global.num_total,get_ptr(b),lgJac,c);    
        
        /*------------------------------------------------------------------ */
        if(printsol || (trace.lgTrace && trace.lgTraceMole ))
        {
                /* print the full matrix */
                fprintf( ioQQQ, "                ");
                for( long i=0; i < mole_global.num_calc; i++ )
                {
                        fprintf( ioQQQ, "      %-4.4s", mole_global.list[i]->label.c_str() );
                }
                fprintf( ioQQQ, " \n" );
                
                fprintf(ioQQQ,"       MOLE old abundances\t%.2f",fnzone);
                for( long i=0; i<mole_global.num_calc; i++ )
                        fprintf(ioQQQ,"\t%.2e", mole.species[i].den );
                fprintf(ioQQQ,"\n" );
                
                for( long i=0; i < mole_global.num_calc; i++ )
                {
                        fprintf( ioQQQ, "       MOLE%2ld %-4.4s", i ,mole_global.list[i]->label.c_str());
                        for( long j=0; j < mole_global.num_calc; j++ )
                        {
                                fprintf( ioQQQ, "%10.2e", c[j][i] );
                        }
                        fprintf( ioQQQ, "%10.2e", b[i] );
                        fprintf( ioQQQ, "\n" );
                }
        }

        /* add positive ions and neutral atoms: ratios are set by ion_solver,
         * we determine abundance of the group as a whole here */
        
        if (lgJac) {
                for(long i=0;i<mole_global.num_calc;i++) 
                {
                        ASSERT(mole_global.list[i]->index == i);
                }
                for (unsigned long j=0; j<nuclide_list.size(); ++j )
                {
                        vector<int> &jlist = nuclide_list[j]->ipMl;
                        if (jlist[0] != -1)
                        {
                                for(long i=0;i<mole_global.num_calc;i++) 
                                {
                                        c[jlist[0]][i] *= MoleMap.fion[j][0];
                                }
                                for (unsigned long ion=1;ion<jlist.size();ion++) 
                                {
                                        double fion = MoleMap.fion[j][ion];
                                        if (jlist[ion] != -1 && fion != 0.0)
                                        {
                                                for(long i=0;i<mole_global.num_calc;i++) 
                                                {
                                                        c[jlist[0]][i] += fion*c[jlist[ion]][i];
                                                }
                                        }
                                }
                        }
                }
                for (unsigned long j=0; j<nuclide_list.size(); ++j )
                {
                        vector<int> &jlist = nuclide_list[j]->ipMl;
                        if (jlist[0] != -1)
                        {
                                for(long i=0;i<mole_global.num_calc;i++) 
                                {
                                        double sum = 0.0;

                                        for (unsigned long ion=0;ion<jlist.size();ion++)
                                        {
                                                if (jlist[ion] != -1)
                                                {
                                                        sum += c[i][jlist[ion]];
                                                }
                                        }
                                        c[i][jlist[0]] = sum; 
                                }                                       
                        }
                }
        }
        
        for (unsigned long j=0; j<nuclide_list.size(); ++j )
        {
                //if (j == 8)
                //      fprintf(ioQQQ,"Nsum1 %s %ld %d %d\n",
                //                        nuclide_list[j]->label().c_str(), j, groupspecies[29]->index,nuclide_list[j]->ipMl[0]);
                vector<int> &jlist = nuclide_list[j]->ipMl;
                if (jlist[0] != -1)
                {
                        double sum = 0.0;
                        for (unsigned long ion=0;ion<jlist.size();ion++)
                        {       
                                if (jlist[ion] != -1)
                                {
                                        //                      if (j == 8)
                                        //      fprintf(ioQQQ,"Nsum %d %15.8g\n",nuclide_list[j]->ipMl[ion],
                                        //                        b[nuclide_list[j]->ipMl[ion]]);
                                        sum += b[jlist[ion]];
                                        b[jlist[ion]] = 0.0;
                                }
                        }
                        b[jlist[0]] = sum;
                }
        }
        
        /* Species are now grouped -- only mole_global.num_compacted elements now active */

        if (*lgConserve)
        {
                // Replace atom rows with conservation constraints
                if (lgJac)
                {
                        for ( unsigned long j = 0; j < nuclide_list.size(); ++j )
                        {
                                long ncons = nuclide_list[j]->ipMl[0];
                                if (ncons != -1)
                                {
                                        ASSERT( mole_global.list[ncons]->isMonatomic() );
                                        double scale=1.0/MoleMap.molElems[j]; //fabs(c[ncons][ncons]);// 
                                        for( long i=0;i<mole_global.num_compacted;i++)
                                        {
                                                if( groupspecies[i]->nNuclide.find(nuclide_list[j]) != groupspecies[i]->nNuclide.end() )
                                                        c[groupspecies[i]->index][ncons] = groupspecies[i]->nNuclide[nuclide_list[j]]*scale;
                                                else
                                                        c[groupspecies[i]->index][ncons] = 0.;
                                                
                                        }
                                }
                        }
                }

                valarray<double> molnow(nuclide_list.size());
                grouped_elems(get_ptr(b2vec), get_ptr(molnow));
                for ( unsigned long j = 0; j < nuclide_list.size(); ++j )
                {
                        long ncons = nuclide_list[j]->ipMl[0];
                        if (ncons != -1)
                        {
                                ASSERT( mole_global.list[ncons]->isMonatomic() );
                                double scale = c[ncons][ncons];
                                b[ncons] = (molnow[j]-MoleMap.molElems[j])*scale;
                                if (false)
                                        if (b[ncons] != 0.0)
                                                fprintf(ioQQQ,"Cons %s err %g rel %g\n",
                                                                  nuclide_list[j]->label().c_str(),b[ncons],
                                                                  (molnow[j]-MoleMap.molElems[j])/SDIV(MoleMap.molElems[j]));
                        }
                }
        }
        
        for( long i=0; i < mole_global.num_compacted; i++ )
        {
                ervals[i] = b[groupspecies[i]->index];
        }
        
        if (lgJac)
        {

                for( long i=0; i < mole_global.num_compacted; i++ )
                {
                        for( long j=0; j < mole_global.num_compacted; j++ )
                        {
                                MAT(amat,i,j) = c[groupspecies[i]->index][groupspecies[j]->index];
                        }                        
                }

                // Replace rows for species with no sources and sinks with
                // an identity
                for(long i=0;i<mole_global.num_compacted;i++)
                {
                        double sum1 = 0.;
                        for (long j=0;j<mole_global.num_compacted;j++)
                        {
                                sum1 += fabs(MAT(amat,j,i));
                        }
                        if (sum1 == 0.0)
                        {
                                ASSERT(ervals[i] == 0.0);
                                MAT(amat,i,i) = 1.0;
                                // fprintf(ioQQQ,"Fixing %ld %s\n",i,groupspecies[i]->label.c_str());
                        }
                }
        }
}

STATIC void grouped_elems(const double bvec[], double mole_elems[])
{
        map<chem_nuclide*, long> nuclide_to_index;
        for (unsigned long j=0; j<nuclide_list.size(); ++j )
        {
                mole_elems[j] = 0.;
                nuclide_to_index[nuclide_list[j].get_ptr()] = j;
        }
        for( long i=0; i < mole_global.num_compacted; i++ )
        {
                if( groupspecies[i]->isIsotopicTotalSpecies() == false )
                        continue;
                
                for (molecule::nNucsMap::const_iterator el = groupspecies[i]->nNuclide.begin(); 
                          el != groupspecies[i]->nNuclide.end(); ++el)
                {
                        mole_elems[nuclide_to_index[el->first.get_ptr()]] += bvec[i]*el->second;
                }
        }
}

void GroupMap::setup(double *b0vec)
{
        valarray<double> calcv(mole_global.num_total);
        bool lgSet;

        for( long i=0;i<mole_global.num_total;i++)
        {
                calcv[i] = mole.species[i].den;
        }

        for (unsigned long j=0; j<nuclide_list.size(); ++j )
        {
                if (nuclide_list[j]->ipMl[0] != -1)
                {
                        double sum = 0.;
                        for (unsigned long ion=0; ion<nuclide_list[j]->ipMl.size(); ion++)
                        {
                                if (nuclide_list[j]->ipMl[ion] != -1)
                                        sum += calcv[nuclide_list[j]->ipMl[ion]];
                        }
                        if (sum > SMALLFLOAT)
                        {
                                double factor = 1./sum;
                                for (unsigned long ion=0; ion<nuclide_list[j]->ipMl.size(); ion++)
                                {
                                        if (nuclide_list[j]->ipMl[ion] != -1)
                                                fion[j][ion] = calcv[nuclide_list[j]->ipMl[ion]]*factor;
                                        else
                                                fion[j][ion] = 0.;
                                }
                        }
                        else
                        {
                                lgSet = false;
                                for (unsigned long ion=0; ion<nuclide_list[j]->ipMl.size(); ion++)
                                {
                                        if (nuclide_list[j]->ipMl[ion] != -1 && !lgSet)
                                        {
                                                fion[j][ion] = 1.0;
                                                lgSet = true;
                                        }
                                        else
                                        {
                                                fion[j][ion] = 0.;
                                        }
                                }
                        }
                        
                        lgSet = false;
                        for (unsigned long ion=0; ion<nuclide_list[j]->ipMl.size(); ion++)
                        {
                                if (nuclide_list[j]->ipMl[ion] != -1)
                                {
                                        if (!lgSet) 
                                                calcv[nuclide_list[j]->ipMl[ion]] = sum;
                                        else
                                                calcv[nuclide_list[j]->ipMl[ion]] = 0.;
                                        lgSet = true;
                                }
                        }
                }
        }       

        for( long i=0; i < mole_global.num_compacted; i++ )
        {
                b0vec[i] = calcv[groupspecies[i]->index];
        }
        
        grouped_elems(get_ptr(b0vec),get_ptr(molElems));

        for (unsigned long i = 0; i<nuclide_list.size(); ++i)
        {
                double densAtom = 0.;
                // deuterium is special case
                if( nuclide_list[i]->el->Z==1 && nuclide_list[i]->A==2 )
                {
                        ASSERT( deut.lgElmtOn );
                        densAtom = deut.gas_phase;
                }
                // skip other isotopes
                else if( !nuclide_list[i]->lgMeanAbundance() )
                        continue;
                else
                {
                        int nelem = nuclide_list[i]->el->Z-1;
                        densAtom = dense.gas_phase[nelem];
                }
                bool lgTest = 
                        ( densAtom < SMALLABUND && molElems[i] < SMALLABUND ) ||
                        ( fabs(molElems[i]- densAtom) <= conv.GasPhaseAbundErrorAllowed*densAtom );
                if( !lgTest )
                        fprintf( ioQQQ, "PROBLEM molElems BAD  %li\t%s\t%.12e\t%.12e\t%.12e\n", 
                                                i, nuclide_list[i]->label().c_str(), nuclide_list[i]->frac, densAtom, molElems[i] );
                
                ASSERT( lgTest );
                molElems[i] = densAtom;
        }

}

void GroupMap::updateMolecules(const valarray<double> & b2 )
{
        DEBUG_ENTRY( "updateMolecules()" );

        for (long mol=0;mol<mole_global.num_calc;mol++)
        {
                mole.species[mol].den = 0.;
        }
        for (long mol=0;mol<mole_global.num_compacted;mol++)
        {
                mole.species[ groupspecies[mol]->index ].den = b2[mol]; /* put derived abundances back into appropriate molecular species */
        }

        // calculate isotopologue densities
        for (long mol=0;mol<mole_global.num_calc;mol++)
        {
                if( mole_global.list[mol]->parentIndex >= 0 )
                {
                        ASSERT( !mole_global.list[mol]->isIsotopicTotalSpecies() );
                        long parentIndex = mole_global.list[mol]->parentIndex;
                        mole.species[mol].den = mole.species[parentIndex].den;
                        for( nNucs_i it = mole_global.list[mol]->nNuclide.begin(); it != mole_global.list[mol]->nNuclide.end(); ++it )
                        {
                                if( !it->first->lgMeanAbundance() )
                                {
                                        mole.species[mol].den *= pow( it->first->frac, it->second );
                                }
                        } 
                }
        }
        
        // calculate densities for monatomic species that had been collapsed into a group
        for (unsigned long j=0; j<nuclide_list.size(); ++j )
        {
                if (nuclide_list[j]->ipMl[0] != -1)
                {
                        double grouptot = mole.species[nuclide_list[j]->ipMl[0]].den;
                        double sum = 0.0;
                        for (unsigned long ion=0;ion<nuclide_list[j]->ipMl.size();ion++)
                        {
                                if (nuclide_list[j]->ipMl[ion] != -1)
                                {
                                        mole.species[nuclide_list[j]->ipMl[ion]].den = grouptot * fion[j][ion];
                                        sum += mole.species[nuclide_list[j]->ipMl[ion]].den;
                                }
                        }
                        ASSERT(fabs(sum-grouptot) <= 1e-10 * fabs(grouptot));
                }
        }
        
        mole.set_isotope_abundances();

        return;
}

STATIC void mole_eval_dynamic_balance(long int num_total, double *b, bool lgJac, multi_arr<double,2> &c)
{
        double source;
        
        DEBUG_ENTRY( "mole_eval_dynamic_balance()" );

        mole_eval_balance(num_total, b, lgJac, c);

        /* >>chng 06 mar 17, comment out test on old full depth - keep old solution if overrun scale */
        if( iteration >= dynamics.n_initial_relax+1 &&
                ( dynamics.lgAdvection || dynamics.lgTimeDependentStatic ) &&
                dynamics.Rate != 0.0 )
        {
                /* Don't use conservation form in matrix solution -- dynamics rate terms make c[][] non-singular */             

                for( long i=0;i<mole_global.num_calc;i++)
                {
                        if (lgJac)
                                c[i][i] -= dynamics.Rate;

                        if( !mole_global.list[i]->isIsotopicTotalSpecies() )
                                continue;

                        b[i] -= mole.species[i].den*dynamics.Rate;

                        if (!mole_global.list[i]->isMonatomic() || mole_global.list[i]->charge < 0 || ! mole_global.list[i]->lgGas_Phase ||
                                ( mole_global.list[i]->isMonatomic() && !mole_global.list[i]->nNuclide.begin()->first->lgMeanAbundance() ) )
                        {
                                b[i] += dynamics.molecules[i];
                        }
                        else if (mole_global.list[i]->charge == 0)
                        {
                                ASSERT( mole_global.list[i]->isMonatomic() );
                                ASSERT( (int)mole_global.list[i]->nNuclide.size() == 1 );
                                const count_ptr<chem_nuclide>& atom = mole_global.list[i]->nNuclide.begin()->first;
                                long nelem = atom->el->Z-1;
                                if( nelem >= LIMELM )                                           
                                        continue;
                                source = 0.0;
                                for ( long ion=dense.IonLow[nelem]; ion<=dense.IonHigh[nelem]; ++ion )
                                {
                                        source += dynamics.Source[nelem][ion] * atom->frac;
                                }
                                b[i] += source;
                        }
                }
        }
}