Code help; loop problem

This is a discussion on Code help; loop problem within the C Programming forums, part of the General Programming Boards category; Hi, I have the following program. It worked great until I added the For loop at the begining, and modified ...

  1. #1
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    Smile Code help; loop problem

    Hi,

    I have the following program. It worked great until I added the For loop at the begining, and modified if((i=0)&&(doy <=1)). Now the output looks good for a couple iterations, but then goes into this endless output of day nan nan nan ~0.035 nan nan nan nan. Any suggestions on how to fix this problem? Many thanks!

    The code:

    Code:
    #define SMA 0.00036			/* DIM scaling parameter for SM curve */
    #define SMB 105.0			/* DIM scaling parameter for SM curve */
    #define FMET 0.59			/* DIM metabolic fraction of NPP; Potter et al. 1993, CHANGE FOR DIFFERENT BIOMES */
    #define FSTR 0.70			/* DIM slow SOC fraction of structural SOC pool; Ise and Moorcroft 2006 */
    #define KSTR 0.40			/* DIM proportional rate K for structural SOC decomposition; Ise and Moorcroft 2006 */
    #define KSLW 0.0093			/* DIM proportional rate K for slow SOC decomposition; Ise and Moorcroft 2006 */
    #define FRAUT 0.53			/* DIM proportion of GPP represented by autotrophic respiration. This value is taken from Choudhury (2001). The origional model used Gifford et al. 2005,
    **                          /* value of 0.46.  CHANGE FOR DIFFERENT BIOMES */
    
    #define ME 0.45				/* DIM Microbial efficiency; McGill et al. 1981; Potter et al. 1993 */
    #define KOPT 0.0301			/* Optimal decomposition rate (1/d) for soil metabolic fraction; Ise and Moorcroft 2006 */
    
    
    #include	    <math.h>
    #include        <stdio.h>
    #include        <stdlib.h>
    #include        <malloc.h>
    #include        <unistd.h>
    
    
    
    int main()
    
    {
    
    
    	int	doy;
    doy=0;
    
    	double	soil_t;		/* surface soil temperature; deg K */
    	double	soil_m;		/* surface soil moisture; % saturation */
    	double	gpp;		/* GPP; g C m-2 d-1 */
    
    
    	double  npp;
    
    	double rmet;
    	double rstr;
    	double rslw;
    
    
    	double	npp_ann_init;	/* Initial NPP pool; g C m-2 yr-1 */
    	double	soil_t_av;	/* long-term avg surface soil T; deg K */
    	double  soil_m_av; 	/* long-term avg JJA soil moisture; % saturation */
    	double  met_c_init;	/* initial soil metabolic C pool; g C m-2; Ise and Moorcroft, 2006 */
    	double  struct_c_init;	/* initial structural soil C pool; g C m-2; Ise and Moorcroft, 2006 */
    	double  slow_c_init;	/* initial slow soil C pool; g C m-2; Ise and Moorcroft, 2006 */
    	double  r_aut;		/* autotrophic respiration; g C m-2 d-1 */
    	double  r_het;		/* heterotrophic respiration; g C m-2 d-1 */
    
    
    
        double dCmet;
    	double dCstr;
    	double dCslw;
    
    	double cmet;
    	double cstr;
    	double cslw;
    
    
    
    
    	double  r_tot;		/* total respiration; g C m-2 d-1 */
    	double  k_met_opt;	/* optimal soil metabolic C decomposition rate; d-1 */
    	double  k_met_av;	/* average soil metabolic C decomposition rate; d-1 */
    	double  k_met;		/* actual soil metabolic C decomp rate; d-1 */
    	double  k_struct;	/* soil structural C decomp rate; d-1 */
    	double  k_slow;		/* soil slow C decomp rate; d-1 */
    
    	double  tmult;		/* DIM 0-1, soil temperature rate response curve */
    	double  tmult_av;	/* DIM 0-1, soil temperature rate response under avg conditions */
    	double  wmult;		/* DIM 0-1, soil moisture rate response curve */
    	double  wmult_av;	/* DIM 0-1, soil moisture rate response under avg conditions */
    	int     flag;		/* DIM 0.0 or 1.0 for spinup or daily run, respectively */
    
    
    /* 1.0 open data input file */
    
    FILE *datain;
    
    int i;
    i=1;
    
    for (i = 0 ; i < 2; i++)
    
    {
    
    /* datain =fopen("/home/jennifer.watts/Carbon_Models/TCF_model_modified/Testing_Spinup/", "r"); */
    datain =fopen("tcf_spinup.txt", "r");
    
    if (datain == NULL)
    {
    	fprintf(stderr, "Can't open input file!\n");
    	exit(-1);
    	}
    
    
    
    
    	while(fscanf(datain,"%d %d %lf %lf %lf %lf %lf %lf %lf %lf %lf",
    	      &flag, &doy, &gpp, &soil_t, &soil_m, &soil_t_av, &soil_m_av, &npp_ann_init, &met_c_init, &struct_c_init, &slow_c_init) != EOF)
    	      {
    
    	   doy++;
    
    
    
    
    
    
    /* address inital values for year 1, day 1, of spin-up*/
    
    	  if((i=0) && (doy <= 1 ))
    	  {
    	      cmet = met_c_init;
    	      cstr = struct_c_init;
    	      cslw = slow_c_init;
    	      rmet = 0;
    	      rstr = 0;
    	      rslw = 0;
       }
    
    
    
    
    
    /* 3.0 Environmental Constraint Calculations*/
    
    
    
    	    k_met_opt = KOPT;
    
    
    
    /* calculate soil temperature rate response (Lloyd and Taylor 1994) */
    
    	   tmult = exp(308.56 * ((1.0 / 66.02) - (1.0 / ((soil_t) - 227.13))));
    
    
    /* calculate soil moisture response (Monsi 1969, Bunnell and Tait 1974, Oberbauer et al. 1991, 1996) */
    
    	   wmult = SMA * (SMB * soil_m - pow(soil_m, 2.0));
    
    /* 4.0 Calculate soil CO2 input and output; soil C pool values */
    
    
    /* calculate decomposition rate constants */
    
    	   k_met = k_met_opt * tmult * wmult;
    	   k_struct = KSTR * k_met;
    	   k_slow = KSLW * k_met;
    
    
    
    	   rmet = (k_met * cmet * (1.0 - ME));
    	   rstr = (k_struct * cstr * (1.0 - ME));
    	   rslw = (k_slow * cslw * (1.0 - ME));
    
    	   r_het = (rmet + rstr + rslw);
    
    	   r_aut = (gpp * FRAUT);
    
    	   r_tot = (r_het + r_aut);
    
    	   npp = (gpp - r_aut);
    
    
    
    
    
           dCmet = (FMET * npp - rmet);
           dCstr = (((1 - FMET) * npp) - rstr - FSTR * cstr);
           dCslw = ((FSTR * cstr) - rslw);
    
    
           cmet += (cmet + dCmet);
           cstr += (cstr + dCstr);
           cslw += (cslw + dCslw);
    
    
    
    /* print out daily updating of carbon pools for spinup run */
    
    
    
    
    
     printf("%d %.3f %.3f %.3f %.3f %.3f %.3f %.3f %.3f\n", doy, cmet, cstr, cslw, npp, r_tot, dCmet, dCstr, dCslw);
    }
    
    fclose(datain);
    
    }
    
    }

  2. #2
    ATH0 quzah's Avatar
    Join Date
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    Posts
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    Code:
    	  if((i=0) && (doy <= 1 ))
    = is for assignment.
    == is for comparison.

    You have in effect: if( 0 && doy <= 1 ) which immediately fails, because 0 && anything is false.


    Quzah.
    Hope is the first step on the road to disappointment.

  3. #3
    Third Eye Babkockdood's Avatar
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    quzah pointed out one of the biggest mistakes beginners make. Be careful not to get the assignment operator and the relational operator mixed up.

  4. #4
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    Thanks so much!

    It seems to be working just fine now.

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