6.3.10.6 Fractional Subscripts

The /SUBGRID keyword in

x(subscripts, /SUBGRID)

forces linear interpolation in x at the specified coordinates. Without this keyword, floating-point subscripts are converted to integer type and the elements corresponding to those integer subscripts are then extracted from the source variable.

This keyword can only be used with numerical arrays x, and only numerical arrays and scalars are allowed as subscripts. The result is doube if x is double, and float otherwise. If /SUBGRID is specified, then /INNER is implied. For example, x([1.2,2.3], [3.3,4.1], /SUBGRID) is equivalent to [x(1.2, 3.3, /SUBGRID), x(2.3, 4.1, /SUBGRID)].