iTOUGH2 capabilities can be applied to non-TOUGH2 models using the PEST interface. The >>>> PRECISION command determines whether single or double precision protocol is to be observed in writing parameter values. Unless a parameter space is greater than 13 characters in width it has no bearing on the precision with which a parameter value is written to a model input file, as this is determined by the width of the parameter space. If keyword SINGLE is selected, exponents are represented by the letter “e”; also if a parameter space is greater than 13 characters in width, only the last 13 spaces are used in writing the number representing the parameter value, any remaining characters within the parameter space being left blank. If keyword DOUBLE is selected,, up to 23 characters can be used to represent a number and the letter “d” is used to represent exponents; also, the double-precision range of real numbers is available.
>>>> EXECUTABLE : “precise.exe < imsingle.in”
>>>> TEMPLATE : 1
>>>> INSTRUCTION : 1
>>>> DECPOINT: SINGLE