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(Shared Arrays): New section.

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Kevin Ryde 2005-02-28 22:46:08 +00:00
parent a323275d0e
commit e2535ee4a5
1 changed files with 65 additions and 61 deletions
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120
doc/ref/api-compound.texi
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@ -1662,6 +1662,7 @@ arrays.
@menu
* Array Syntax::
* Array Procedures::
* Shared Arrays::
* Accessing Arrays from C::
@end menu
@ -1878,64 +1879,6 @@ a @result{} #2((#f #f) (#f #t))
@end example
@end deffn
@deffn {Scheme Procedure} make-shared-array oldarray mapfunc bound @dots{}
@deffnx {C Function} scm_make_shared_array (oldarray, mapfunc, boundlist)
@code{make-shared-array} can be used to create shared subarrays of other
arrays. The @var{mapper} is a function that translates coordinates in
the new array into coordinates in the old array. A @var{mapper} must be
affine, and its range must stay within the bounds of the old array, but
it can be otherwise arbitrary. A simple example:
@lisp
(define fred (make-array #f 8 8))
(define freds-diagonal
(make-shared-array fred (lambda (i) (list i i)) 8))
(array-set! freds-diagonal 'foo 3)
(array-ref fred 3 3) @result{} foo
(define freds-center
(make-shared-array fred (lambda (i j) (list (+ 3 i) (+ 3 j))) 2 2))
(array-ref freds-center 0 0) @result{} foo
@end lisp
@end deffn
@deffn {Scheme Procedure} shared-array-increments array
@deffnx {C Function} scm_shared_array_increments (array)
For each dimension, return the distance between elements in the root vector.
@end deffn
@deffn {Scheme Procedure} shared-array-offset array
@deffnx {C Function} scm_shared_array_offset (array)
Return the root vector index of the first element in the array.
@end deffn
@deffn {Scheme Procedure} shared-array-root array
@deffnx {C Function} scm_shared_array_root (array)
Return the root vector of a shared array.
@end deffn
@deffn {Scheme Procedure} transpose-array array dim1 @dots{}
@deffnx {C Function} scm_transpose_array (array, dimlist)
Return an array sharing contents with @var{array}, but with
dimensions arranged in a different order. There must be one
@var{dim} argument for each dimension of @var{array}.
@var{dim1}, @var{dim2}, @dots{} should be integers between 0
and the rank of the array to be returned. Each integer in that
range must appear at least once in the argument list.
The values of @var{dim1}, @var{dim2}, @dots{} correspond to
dimensions in the array to be returned, and their positions in the
argument list to dimensions of @var{array}. Several @var{dim}s
may have the same value, in which case the returned array will
have smaller rank than @var{array}.
@lisp
(transpose-array '#2((a b) (c d)) 1 0) @result{} #2((a c) (b d))
(transpose-array '#2((a b) (c d)) 0 0) @result{} #1(a d)
(transpose-array '#3(((a b c) (d e f)) ((1 2 3) (4 5 6))) 1 1 0) @result{}
#2((a 4) (b 5) (c 6))
@end lisp
@end deffn
@deffn {Scheme Procedure} enclose-array array dim1 @dots{}
@deffnx {C Function} scm_enclose_array (array, dimlist)
@var{dim1}, @var{dim2} @dots{} should be nonnegative integers less than
@ -2142,6 +2085,67 @@ omitted, in which case it defaults to the value returned by
@code{(current-output-port)}.
@end deffn
@node Shared Arrays
@subsubsection Shared Arrays
@deffn {Scheme Procedure} make-shared-array oldarray mapfunc bound @dots{}
@deffnx {C Function} scm_make_shared_array (oldarray, mapfunc, boundlist)
@code{make-shared-array} can be used to create shared subarrays of other
arrays. The @var{mapper} is a function that translates coordinates in
the new array into coordinates in the old array. A @var{mapper} must be
affine, and its range must stay within the bounds of the old array, but
it can be otherwise arbitrary. A simple example:
@lisp
(define fred (make-array #f 8 8))
(define freds-diagonal
(make-shared-array fred (lambda (i) (list i i)) 8))
(array-set! freds-diagonal 'foo 3)
(array-ref fred 3 3) @result{} foo
(define freds-center
(make-shared-array fred (lambda (i j) (list (+ 3 i) (+ 3 j))) 2 2))
(array-ref freds-center 0 0) @result{} foo
@end lisp
@end deffn
@deffn {Scheme Procedure} shared-array-increments array
@deffnx {C Function} scm_shared_array_increments (array)
For each dimension, return the distance between elements in the root vector.
@end deffn
@deffn {Scheme Procedure} shared-array-offset array
@deffnx {C Function} scm_shared_array_offset (array)
Return the root vector index of the first element in the array.
@end deffn
@deffn {Scheme Procedure} shared-array-root array
@deffnx {C Function} scm_shared_array_root (array)
Return the root vector of a shared array.
@end deffn
@deffn {Scheme Procedure} transpose-array array dim1 @dots{}
@deffnx {C Function} scm_transpose_array (array, dimlist)
Return an array sharing contents with @var{array}, but with
dimensions arranged in a different order. There must be one
@var{dim} argument for each dimension of @var{array}.
@var{dim1}, @var{dim2}, @dots{} should be integers between 0
and the rank of the array to be returned. Each integer in that
range must appear at least once in the argument list.
The values of @var{dim1}, @var{dim2}, @dots{} correspond to
dimensions in the array to be returned, and their positions in the
argument list to dimensions of @var{array}. Several @var{dim}s
may have the same value, in which case the returned array will
have smaller rank than @var{array}.
@lisp
(transpose-array '#2((a b) (c d)) 1 0) @result{} #2((a c) (b d))
(transpose-array '#2((a b) (c d)) 0 0) @result{} #1(a d)
(transpose-array '#3(((a b c) (d e f)) ((1 2 3) (4 5 6))) 1 1 0) @result{}
#2((a 4) (b 5) (c 6))
@end lisp
@end deffn
@node Accessing Arrays from C
@subsubsection Accessing Arrays from C