several checks on the code's behavior are made in 
CheckSanity.c

NDEBUG is set when debugging is turned off, and is 
undefined when the debug version is built
#if !defined(NDEBUG)
	ChkSumCon(0);
#endif

pclint - options for perfect line through std2 points to c:\lint\perfect.lnt

==================================================================
unit integration checks:
there are currently two.  The emission line array is tested in routine LineSet1
where a fake emission line with local emissivty 1e-10, label "Unit", wavelength 1,
is passed through the lines arrays.   It is then checked at the end of the calculation
in routine PrtFinal.

a similar test is done with the continuum transfer arrays.  the continuum is actually
defined wth rfield.nflux points, the loops are always up to < rfield.nflux.  In metdif
the local emissivty at [rfield.nflux] is set to 1e-10f, and then passed through the
continuum transfer arrays.  This is also checked in PrtFinal.

the number is actually 1e-10 so that it does not overflow on 32-bit machines.

==================================================================
/* following routine provides a debugging hook into the main line array 
 * loops over whole array and finds every line that matches length,
 * the wavelength, the argument to the function
 * put breakpoint inside if test */
long debugLine( long int length )


==================================================================
photoionization rate:
 * GammaPrtRate will print photo rates for all shells of a ion and element 

==================================================================
trace convergence number
number indicates level of trace, 
 gt 3 includes ConvIoniz
 3 

==================================================================
all changes in code have timestamp like
>>>chng 99 dec 06
no space inside >>>chng but spaces all around date