src/data/listoflist.lisp

   1 ;;; -*- mode: lisp -*-
   2
   3 ;;; Time-stamp: <2009-08-27 08:36:35 tony>
   4 ;;; Creation:   <2008-09-08 08:06:30 tony>
   5 ;;; File:       listoflist.lisp
   6 ;;; Author:     AJ Rossini <blindglobe@gmail.com>
   7 ;;; Copyright:  (c) 2007-2008, AJ Rossini <blindglobe@gmail.com>.  BSD.
   8 ;;; Purpose:    Manipulating structures which are lists of lists
   9 ;;;             with matrix-likes and dataframe-likes.
  10
  11 ;;; What is this talk of 'release'? Klingons do not make software
  12 ;;; 'releases'.  Our software 'escapes', leaving a bloody trail of
  13 ;;; designers and quality assurance people in its wake.
  14
  15 (in-package :cls-data)
  16
  17 ;; We currently assume that the list-of-list representation is in
  18 ;; row-major form, i.e. that lists represent rows and not columns.
  19 ;; The original lisp-stat had the other way around.  We could augment
  20 ;; the top-level list with a property to check orientation
  21 ;; (row-major/column-major), but this hasn't been done yet.
  22
  23 ;; See XARRAY's listoflist example for more details and support
  24 ;; functions (migrated from here to there).
  25
  26 (defun listoflist->matrix-like (lol &key
  27                                 (orientation :row-major)
  28                                 (coerce-to 'double-float))
  29   "From a listoflists structure of numbers, return a matrix-like.
  30
  31 FIXME: need to verify that the listoflists is a valid structure (same
  32 size rows, typing if required, etc.
  33
  34 FIXME: need to grep special variables to make the right kind of
  35 matrix-like.
  36
  37 <example>
  38   (defparameter *lol-ml-test*
  39       (list (list 1d0 1d0 2.1d0)
  40             (list 2d0 2d0 1.1d0)))
  41   (length *lol-ml-test*)
  42   (length (elt *lol-ml-test* 0))
  43
  44   (defparameter *lol-ml-result* (listoflist->matrix-like *lol-ml-test*))
  45   (matrix-dimensions *lol-ml-result*)
  46 </example>"
  47   (declare (ignorable coerce-to))
  48   (let ((n (length lol))
  49         (p (length (elt lol 0))))
  50     (let ((result (make-matrix  n p :initial-element 0d0)))
  51       (dotimes (i n)
  52         (dotimes (j p)
  53           (if (equal orientation :row-major)
  54               (setf (mref result i j) (coerce (elt (elt lol i) j) coerce-to))
  55               (setf (mref result i j) (coerce (elt (elt lol j) i) coerce-to)))))
  56       result)))
  57
  58
  59 ;; the following will be handy to help out folks adjust.  It should
  60 ;; provide a means to write code faster and better.
  61 (defun listoflist->dataframe (lol) ; &key (type :row-major))
  62   "Create a cases-by-variables data frame consisting of numeric data,
  63 from a ROW-MAJOR list-of-lists representation.  A COLUMN-MAJOR
  64 representation should be handled using the transpose-listoflists
  65 function."
  66   (if (lists-of-same-size lol)
  67       (make-dataframe  (listoflist->array lol))
  68       (error "make-data-set-from-lists: no combining different length lists"))
  69   (error "make-data-set-from-lists: proposed name exists"))
  70
  71