Syntax:
array-row-major-index array &rest subscripts => index
Arguments and Values:
array---an array.
subscripts---a list of valid array indices for the array.
index---a valid array row-major index for the array.
Description:
Computes the position according to the row-major ordering of array for the element that is specified by subscripts, and returns the offset of the element in the computed position from the beginning of array.
For a one-dimensional array, the result of array-row-major-index equals subscript.
array-row-major-index ignores fill pointers.
Examples:
(setq a (make-array '(4 7) :element-type '(unsigned-byte 8))) (array-row-major-index a 1 2) => 9 (array-row-major-index (make-array '(2 3 4) :element-type '(unsigned-byte 8) :displaced-to a :displaced-index-offset 4) 0 2 1) => 9
Affected By: None.
Exceptional Situations: None.
See Also: None.
Notes:
A possible definition of array-row-major-index, with no error-checking, is
(defun array-row-major-index (a &rest subscripts) (apply #'+ (maplist #'(lambda (x y) (* (car x) (apply #'* (cdr y)))) subscripts (array-dimensions a))))