;;;; "arraymap.scm", applicative routines for arrays in Scheme.
;;; Copyright (C) 1993, 2003 Aubrey Jaffer
;
;Permission to copy this software, to modify it, to redistribute it,
;to distribute modified versions, and to use it for any purpose is
;granted, subject to the following restrictions and understandings.
;
;1. Any copy made of this software must include this copyright notice
;in full.
;
;2. I have made no warranty or representation that the operation of
;this software will be error-free, and I am under no obligation to
;provide any services, by way of maintenance, update, or otherwise.
;
;3. In conjunction with products arising from the use of this
;material, there shall be no use of my name in any advertising,
;promotional, or sales literature without prior written consent in
;each case.
(require 'array)
;;@code{(require 'array-for-each)}
;;@ftindex array-for-each
;;@args array0 proc array1 @dots{}
;;@var{array1}, @dots{} must have the same number of dimensions as
;;@var{array0} and have a range for each index which includes the range
;;for the corresponding index in @var{array0}. @var{proc} is applied to
;;each tuple of elements of @var{array1} @dots{} and the result is stored
;;as the corresponding element in @var{array0}. The value returned is
;;unspecified. The order of application is unspecified.
(define (array-map! ra0 proc . ras)
(define (ramap rdims inds)
(if (null? (cdr rdims))
(do ((i (+ -1 (car rdims)) (+ -1 i))
(is (cons (+ -1 (car rdims)) inds)
(cons (+ -1 i) inds)))
((negative? i))
(apply array-set! ra0
(apply proc (map (lambda (ra) (apply array-ref ra is)) ras))
is))
(let ((crdims (cdr rdims)))
(do ((i (+ -1 (car rdims)) (+ -1 i)))
((negative? i))
(ramap crdims (cons i inds))))))
(ramap (reverse (array-dimensions ra0)) '()))
;;@args prototype proc array1 array2 @dots{}
;;@var{array2}, @dots{} must have the same number of dimensions as
;;@var{array1} and have a range for each index which includes the
;;range for the corresponding index in @var{array1}. @var{proc} is
;;applied to each tuple of elements of @var{array1}, @var{array2},
;;@dots{} and the result is stored as the corresponding element in a
;;new array of type @var{prototype}. The new array is returned. The
;;order of application is unspecified.
(define (array-map prototype proc ra1 . ras)
(define nra (apply make-array prototype (array-dimensions ra1)))
(apply array-map! nra proc ra1 ras)
nra)
;;@args proc array0 @dots{}
;;@var{proc} is applied to each tuple of elements of @var{array0} @dots{}
;;in row-major order. The value returned is unspecified.
(define (array-for-each proc . ras)
(define (rafe rdims inds)
(if (null? (cdr rdims))
(let ((sdni (reverse (cons #f inds))))
(define lastpair (last-pair sdni))
(do ((i 0 (+ 1 i)))
((> i (+ -1 (car rdims))))
(set-car! lastpair i)
(apply proc (map (lambda (ra) (apply array-ref ra sdni)) ras))))
(let ((crdims (cdr rdims))
(ll (+ -1 (car rdims))))
(do ((i 0 (+ 1 i)))
((> i ll))
(rafe crdims (cons i inds))))))
(rafe (array-dimensions (car ras)) '()))
;;@args array
;;Returns an array of lists of indexes for @var{array} such that, if
;;@var{li} is a list of indexes for which @var{array} is defined,
;;(equal? @var{li} (apply array-ref (array-indexes @var{array})
;;@var{li})).
(define (array-indexes ra)
(let ((ra0 (apply make-array '#() (array-dimensions ra))))
(array-index-map! ra0 list)
ra0))
;;@args array proc
;;applies @var{proc} to the indices of each element of @var{array} in
;;turn. The value returned and the order of application are
;;unspecified.
;;
;;One can implement @var{array-index-map!} as
;;@example
;;(define (array-index-map! ra fun)
;; (array-index-for-each
;; ra
;; (lambda is (apply array-set! ra (apply fun is) is))))
;;@end example
(define (array-index-for-each ra fun)
(define (ramap rdims inds)
(if (null? (cdr rdims))
(do ((i (+ -1 (car rdims)) (+ -1 i))
(is (cons (+ -1 (car rdims)) inds)
(cons (+ -1 i) inds)))
((negative? i))
(apply fun is))
(let ((crdims (cdr rdims)))
(do ((i (+ -1 (car rdims)) (+ -1 i)))
((negative? i))
(ramap crdims (cons i inds))))))
(if (zero? (array-rank ra))
(fun)
(ramap (reverse (array-dimensions ra)) '())))
;;@args array proc
;;applies @var{proc} to the indices of each element of @var{array} in
;;turn, storing the result in the corresponding element. The value
;;returned and the order of application are unspecified.
;;
;;One can implement @var{array-indexes} as
;;@example
;;(define (array-indexes array)
;; (let ((ra (apply make-array '#() (array-dimensions array))))
;; (array-index-map! ra (lambda x x))
;; ra))
;;@end example
;;Another example:
;;@example
;;(define (apl:index-generator n)
;; (let ((v (make-vector n 1)))
;; (array-index-map! v (lambda (i) i))
;; v))
;;@end example
(define (array-index-map! ra fun)
(array-index-for-each ra
(lambda is (apply array-set! ra (apply fun is) is))))
;;@args destination source
;;Copies every element from vector or array @var{source} to the
;;corresponding element of @var{destination}. @var{destination} must
;;have the same rank as @var{source}, and be at least as large in each
;;dimension. The order of copying is unspecified.
(define (array:copy! dest source)
(array-map! dest identity source))