src/basics/lsbasics.lsp

   1 ;;; -*- mode: lisp -*-
   2 ;;; Copyright (c) 2005--2008, by A.J. Rossini <blindglobe@gmail.com>
   3 ;;; See COPYRIGHT file for any additional restrictions (BSD license).
   4 ;;; Since 1991, ANSI was finally finished.  Edited for ANSI Common Lisp.
   5
   6 ;;;; lsbasics -- Low level Lisp-Stat functions
   7 ;;;;
   8 ;;;; Copyright (c) 1991, by Luke Tierney. Permission is granted for
   9 ;;;; unrestricted use.
  10
  11 (in-package :lisp-stat-basics)
  12
  13 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  14 ;;;;
  15 ;;;;                    Array Permutation Functions
  16 ;;;;
  17 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  18
  19 (defun permute-indices (x y perm check)
  20   "Args: (x y perm check).
  21 permute x into y using perm; all should be vectors; If check is TRUE
  22 the routine will check to make sure no indices are reused, but x
  23 will be destroyed."
  24   (let ((rank (length x)))
  25     (declare (fixnum rank))
  26     (dotimes (i rank)
  27       (declare (fixnum i))
  28       (let ((k (aref perm i)))
  29         (if (not (fixnump k)) (error "bad permutation sequence - ~a" perm))
  30         (if (or (< k 0) (>= k rank))
  31             (error "bad permutation sequence - ~a" perm))
  32         (setf (aref y i) (aref x k))
  33         ;; to insure dimensions are not re-used
  34         (if check (setf (aref x k) NIL))))))
  35
  36 (defun indices-from-rowmajor (a k result)
  37   "Args: (a k result).
  38 Compute indices in a from rowmajor index k, put in vector result."
  39   (declare (fixnum k))
  40
  41   (if (not (arrayp a)) (error "not an array - ~a" a))
  42   (if (or (> 0 k) (>= k (array-total-size a))) (error "index out of range"))
  43
  44   (let ((face 1)
  45         (rank (array-rank a))
  46         (dim (array-dimensions a)))
  47     (declare (fixnum face rank))
  48     (let ((cdim (make-next-element dim)))
  49       (dotimes (i rank)
  50         (declare (fixnum i))
  51         (setf face (* face (get-next-element cdim i)))))
  52     (let ((cdim (make-next-element dim)))
  53       (dotimes (i rank)
  54         (setf face (/ face (get-next-element cdim i)))
  55         (setf (aref result i) (floor (/ k face)))
  56         (setf k (rem k face))))))
  57
  58 (defun translate-index (i result x perm indices oldindices ilist)
  59   "Args: (i result x perm indices oldindices ilist).
  60 Translate row major index in original array to row major index in new
  61 array. Use indices vectors and ilist for temporary storage."
  62   (declare (fixnum i))
  63   (let ((rank (array-rank x)))
  64     (declare (fixnum rank))
  65     (indices-from-rowmajor x i oldindices)
  66     (permute-indices oldindices indices perm nil)
  67     (do ((next ilist (rest next))
  68          (k 0 (+ k 1)))
  69         ((not (and (< k rank) (consp next))))
  70       (setf (first next) (aref indices k)))
  71     (apply #'array-row-major-index result ilist)))
  72
  73 (defun permute-array (x perm)
  74   "Args: (a p)
  75 Returns a copy of the array A permuted according to the permutation P."
  76   (if (not (arrayp x)) (error "not an array - ~a" x))
  77   (check-sequence perm)
  78   (if (/= (length perm) (array-rank x))
  79     (error "bad permutation sequence - ~a" perm))
  80   (let* ((perm (coerce perm 'vector))
  81          (rank (array-rank x))
  82          (dim (make-array rank))
  83          (olddim (coerce (array-dimensions x) 'vector)))
  84     (declare (fixnum rank))
  85     ;; construct new dimension vector
  86     (permute-indices olddim dim perm t)
  87     ;; make result array and the index vectors and lists */
  88     (let* ((result (make-array (coerce dim 'list)))
  89           (indices (make-array rank))
  90           (oldindices (make-array rank))
  91           (ilist (make-list rank))
  92           (data (compound-data-seq x))
  93           (result_data (compound-data-seq result))
  94           (n (length data)))
  95       (declare (fixnum n))
  96       (dotimes (i rank)
  97         (declare (fixnum i))
  98         (setf (aref oldindices i) (list nil)))
  99       ;; fill in the result
 100       (if (/= n (length result_data)) (error "bad data"))
 101       (dotimes (i n result)
 102         (declare (fixnum i))
 103         (let ((k (translate-index i result x perm indices oldindices ilist)))
 104           (declare (fixnum k))
 105           (setf (aref result_data k) (aref data i)))))))
 106
 107 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 108 ;;;;
 109 ;;;;              SUM, PROD, COUNT-ELEMENTS, and MEAN Functions
 110 ;;;;
 111 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 112
 113 (defun sum-1 (x)
 114   (if (numberp x)
 115     x
 116     (let ((seq (compound-data-seq x))
 117           (sum 0))
 118       (if (consp seq)
 119         (dolist (x seq sum)
 120           (incf sum (+ sum (if (numberp x) x (sum-1 x))))) ;; was setf
 121         (let ((n (length seq)))
 122           (declare (fixnum n))
 123           (dotimes (i n sum)
 124             (declare (fixnum i))
 125             (let ((x (aref seq i)))
 126               (setf sum (+ sum (if (numberp x) x (sum-1 x)))))))))))
 127
 128 ;; incr
 129
 130 (defun sum (&rest args)
 131 "Args: (&rest number-data)
 132 Returns the sum of all the elements of its arguments. Returns 0 if there
 133 are no arguments. Vector reducing."
 134   (if args
 135     (sum-1 (if (rest args) args (first args)))
 136     0))
 137
 138
 139
 140 (defun prod-1 (x)
 141   (if (numberp x)
 142     x
 143     (let ((seq (compound-data-seq x))
 144           (prod 1))
 145       (if (consp seq)
 146         (dolist (x seq prod)
 147           (setf prod (* prod (if (numberp x) x (prod-1 x)))))
 148         (let ((n (length seq)))
 149           (declare (fixnum n))
 150           (dotimes (i n prod)
 151             (declare (fixnum i))
 152             (let ((x (aref seq i)))
 153               (setf prod (* prod (if (numberp x) x (prod-1 x)))))))))))
 154
 155 (defun prod (&rest args)
 156 "Args: (&rest number-data)
 157 Returns the product of all the elements of its arguments. Returns 1 if there
 158 are no arguments. Vector reducing."
 159   (if args
 160     (prod-1 (if (rest args) args (first args)))
 161     1))
 162
 163 (defun count-elements (x)
 164 "Args: (number &rest more-numbers)
 165 Returns the number of its arguments. Vector reducing"
 166   (if (compound-data-p x)
 167     (let ((seq (compound-data-seq x))
 168           (count 0))
 169       (if (consp seq)
 170         (dolist (x seq count)
 171           (incf count (if (compound-data-p x) (count-elements x) 1)))
 172         (let ((n (length seq)))
 173           (declare (fixnum n))
 174           (dotimes (i n count)
 175             (declare (fixnum i))
 176             (let ((x (aref seq i)))
 177               (incf count (if (compound-data-p x) (count-elements x) 1)))))))
 178     1))
 179
 180
 181 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 182 ;;;;
 183 ;;;;                    IF-ELSE Functions
 184 ;;;;
 185 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 186
 187 (defun if-else (a x y)
 188 "Args: (first x y)
 189 Takes simple or compound data items A, X and Y and returns result
 190 of elementswise selection, from X if A is not NIL, otherwise from Y."
 191   (flet ((base-if-else (a x y) (if a x y)))
 192     (recursive-map-elements #'base-if-else #'if-else a x y)))