SCM

5.5.2: Array Mapping

(require 'array-for-each)

Function: array-map! array0 proc array1 ...

If array1, ... are arrays, they must have the same number of dimensions as array0 and have a range for each index which includes the range for the corresponding index in array0. If they are scalars, that is, not arrays, vectors, or strings, then they will be converted internally to arrays of the appropriate shape. proc is applied to each tuple of elements of array1 ... and the result is stored as the corresponding element in array0. The value returned is unspecified. The order of application is unspecified.

Function: serial-array-map! array0 proc array1 ...

Same as array-map!, but guaranteed to apply proc in row-major order.

Function: array-for-each proc array0 ...

proc is applied to each tuple of elements of array0 ... in row-major order. The value returned is unspecified.

Function: array-index-map! array proc

applies proc to the indices of each element of array in turn, storing the result in the corresponding element. The value returned and the order of application are unspecified.

One can implement array-indexes as

(define (array-indexes array)
    (let ((ra (apply make-array #f (array-shape array))))
      (array-index-map! ra (lambda x x))
      ra))

Another example:

(define (apl:index-generator n)
    (let ((v (make-uniform-vector n 1)))
      (array-index-map! v (lambda (i) i))
      v))

Function: scalar->array scalar array prototype

Returns a uniform array of the same shape as array, having only one shared element, which is eqv? to scalar. If the optional argument prototype is supplied it will be used as the prototype for the returned array. Otherwise the returned array will be of the same type as array if that is possible, and a conventional array if it is not. This function is used internally by array-map! and friends to handle scalar arguments.