array-row-major-index array {&rest subscripts} => index
array---an array.
subscripts---a list of valid array indices for the array.
index---a valid array row-major index for the array.
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.
(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
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))))
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