The HST Parameter File

   

Each parameter file starts with the first line

! HST_SLAVE PARAMETER FILE

This line is used to check whether or not a supply file is an HST parameter file. (This check is case sensitive.)

Generally all lines starting with an explanation mark are comment lines  and will be ignored by HST_SLAVE. Similarly, an explanation mark may appear on a line following a keyword / value pair; this too is a comment and is ignored.

White space (blank lines), and comment lines are used to break up the parameters into logically associated groups, and in-line comments are used to explain the parameter and associated values. None of this is compulsory, but it recommended practice. (hst_slave can handle input of parameters in any order, but hst_master nevertheless produces them in a clear and logical order.)

The parameters are defined using keyword / value pairs, separated by an equals sign. White space  (blank spaces) is ignored. e.g.

FF_POSTFIX = .edf

FF_FILE_INTERVAL =    100 ! Interval between flat-field files
 
TAKE_LOGARITHM = YES ! Take log of projection values
 
ANGLE_BETWEEN_PROJECTIONS =    0.200000 ! Increment angle in degrees

Keywords  are single tokens, with underscores used to make meaningful identifiers. At present the keyword parsing is case sensitive, and all keywords are upper-case. Different keywords take different type of values : character string, integer, logical, and real values.

Character string values are sequences of characters, without any delimiters. (At present trailing blanks cannot be defined, but do not need to be defined.)

Integer and real values are simple. Note: An integer value can be used without the decimal point for a real value.

Logical values are set with YES or NO.