Expressions

You can use expressions to define data sources in several of Wintrack's custom variable definition file statements. Expressions consists of numeric constants and names which are combined using the unary and binary operators and, as necessary, parentheses.

	Unary operators		Binary operators
-	negative	+	addition
!	absolute value	-	subtraction
#	substitute missing values by 0	*	multiplication
&	substitute missing values by 0,	/	division
	all other values by 1	%	remainder or integer division
[ ]	round to integer	@	transform to preference scores
{ }	substitute non-zero values by 1	>	greater than
>	shift array elements up	<	less than
<	shift array elements down
tLog|	log10(1+x) transform
tSqrt|	sqrt(x) transform
tAsinSqrt|	arcsin (sqrt(x)) transform
tAtan|	arctan (x) transform

Example for use of @ operator: A02@0.2314 transforms each element x of the data array A02 to a preference score P relative to a chance threshold of C=0.2314 using the formula
P=x(1-C)/[x(1-C)+C(1-x)]. If x=0 then P=0. Similarly if x=1 then P=1. If x=C then P=0.5.

See Managing custom variable definition files to learn more on custom data analysis in Wintrack.