parse_caseb.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 */
/*ParseCaseB - parse the Case A, B, or C command */
#include "cddefines.h"
#include "opacity.h"
#include "parser.h"

/*ParseCaseB - parse the Case A, B, or C command */
void ParseCaseB( Parser &p )
{
        DEBUG_ENTRY( "ParseCaseB()" );

        /* which case do we do? */
        if( p.nMatch(" A ") )
        {
                opac.lgCaseB = false;
//              rfield.lgInducProcess = false;
        }
        else if( p.nMatch(" B ") )
        {
                opac.lgCaseB = true;
//              rfield.lgInducProcess = false;
        }
        else if( p.nMatch(" C ") )
                opac.lgCaseB = false;

        /* difference between Case A and Case C is in induced processes -
         * do not include them in Case A or Case B */
        /* optional optical depth in Ly a */
        opac.tlamin = (realnum)p.FFmtRead();
        if( p.lgEOL() )
        {
                /* optical depths not specified - use defaults for cases A and B */ 
                if( opac.lgCaseB )
                        /* set default to 1e5 to get more realistic conditions in H+ region.
                         * Very large tau caused extreme Lya trapping, photoionization rates, 
                         * & radiation pressure*/
                        opac.tlamin = 1e5f;
                else
                        /* Case A or Case C - Lyman lines optically thin */
                        opac.tlamin = 1e-5f;
        }
        else
                opac.tlamin = exp10(opac.tlamin);

        /* Hummer and Storey case B; no collisions from n=1, 2 (usually in) */
        if( p.nMatch("HUMM") )
                opac.lgCaseB_HummerStorey = true;

        /* the NO PHOTOIONIZATION option, turns off excited state photoionization */
        if( p.nMatch("NO PH") )
                opac.lgCaseB_no_photo = true;

        /* the NO PDEST option, turns off line destruction by background opacities */
        if( p.nMatch("NO PDE") )
                opac.lgCaseB_no_pdest = true;

        return;
}