long double collect_dust(long double last_mass, long double *new_dust, 

						 long double *new_gas,

						 long double a, long double e, 

						 long double crit_mass, dust_pointer dust_band)

{

	long double	mass_density;

	long double	temp1;

	long double	temp2;

	long double	temp;

	long double	temp_density;

	long double	bandwidth;

	long double	width;

	long double	volume;

	long double	gas_density = 0.0;

	long double	new_mass;

	long double	next_mass;

	long double	next_dust = 0;

	long double	next_gas = 0;

	printf ("\nStart crit_mass :%.2LE\n",crit_mass);	

	temp = last_mass / (1.0 + last_mass);
	printf ("Modified temp:%.2LE\n",temp );

	reduced_mass = pow(temp,(1.0 / 4.0));
	printf ("reduced_mass:%.2LE\n",reduced_mass );
	if ( !temp ) exit (1);

	r_inner = inner_effect_limit(a, e, reduced_mass);

	r_outer = outer_effect_limit(a, e, reduced_mass);

	

	if ((r_inner < 0.0))

		r_inner = 0.0;

	

	if ((dust_band == NULL)){
		printf("dustband Null\n");

		return(0);
		}

	else  

	{

		if ((dust_band->dust_present == FALSE))

			temp_density = 0.0;

		else 

			temp_density = dust_density;

			

		if (((last_mass < crit_mass) || (dust_band->gas_present == FALSE))){

			mass_density = temp_density;
			printf(" mass_density %LE = temp_density %LE \n",mass_density,temp_density);
		} else
		{
			printf("line 84\n");    
			mass_density = K * temp_density / (1.0 + sqrt(crit_mass / last_mass)

										* (K - 1.0));
			printf(" mass_density %LE \n temp_density %LE \n crit_mass %LE \n last_mass %LE \n K %LE \n " ,  mass_density ,	temp_density,	crit_mass, last_mass, K );
		

			printf(" mass_density %LE = temp_density %LE \n",mass_density,temp_density);

			gas_density = mass_density - temp_density;


		}

		

		if (((dust_band->outer_edge <= r_inner)

		  || (dust_band->inner_edge >= r_outer)))

		{
			printf ("CD1 Last Mass :%.2LE\n",last_mass );

			return(collect_dust(last_mass, new_dust, new_gas,

								a,e,crit_mass, dust_band->next_band));

		}

		else

		{

			bandwidth = (r_outer - r_inner);

			

			temp1 = r_outer - dust_band->outer_edge;

			if (temp1 < 0.0)

				temp1 = 0.0;

			width = bandwidth - temp1;

			

			temp2 = dust_band->inner_edge - r_inner;

			if (temp2 < 0.0)

				temp2 = 0.0;

			width = width - temp2;

			

			temp = 4.0 * PI * pow(a,2.0) * reduced_mass

				* (1.0 - e * (temp1 - temp2) / bandwidth);
			printf ( "start volume: %LE \n",volume );

			volume = temp * width;

			printf ( "End volume: %LE \n",volume );


			new_mass  = volume * mass_density;

			printf ( " Volume: %LE * mass_density: %LE = new_mass : %LE \n",
						  volume ,  mass_density , new_mass );

			*new_gas  = volume * gas_density;

			*new_dust = new_mass - *new_gas;

			printf ("CD2 Last Mass :%.2LE\n",last_mass );

			next_mass = collect_dust(last_mass, &next_dust, &next_gas,

									 a,e,crit_mass, dust_band->next_band);

			printf ("CD2 Next Mass :%.2LE\n",next_mass );

			*new_gas  = *new_gas + next_gas;



			printf ("End return newmass: %LE + Next_mass :%LE = %LE \n" , new_mass , next_mass , new_mass + next_mass ); 			

			return(new_mass + next_mass);

		}

	}

}


compiled using gcc 4.0.3
Description of behavior 

   the var crit_mass is passed to this function with the value NaN, if i print it on line ## then function runs fine, if I do not print it the NaN value transfers to other vars and causes a infinit loop.

 This seems very starnge behavior. 

Any suggestions as to what might be causing this?