;    Copyright (C) 2006  Will M. Farr <farr@mit.edu>
;
;    This program is free software; you can redistribute it and/or modify
;    it under the terms of the GNU General Public License as published by
;    the Free Software Foundation; either version 2 of the License, or
;    (at your option) any later version.
;
;    This program is distributed in the hope that it will be useful,
;    but WITHOUT ANY WARRANTY; without even the implied warranty of
;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;    GNU General Public License for more details.
;
;    You should have received a copy of the GNU General Public License along
;    with this program; if not, write to the Free Software Foundation, Inc.,
;    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


(module maps-test "generics.ss"
  (require "maps.ss")
  (require "tuples.ss")
  (require "manifolds.ss")
  (require (planet "test.ss" ("schematics" "schemeunit.plt" 2)))
  
  (provide maps-test-suite)
  
  (define rectangular (make <chart> 
                            :chi (lambda (x) x)
                            :chiinv (lambda (x) x)
                            :dim 3))
  
  (define chi (slot-ref rectangular 'chi))
  (define chiinv (slot-ref rectangular 'chiinv))
  
  (define R3 (make <manifold> :standard-chart rectangular :dim 3))
  
  (define-named-coordinates (x y z) rectangular)
  
  (define (mu m)
    (let ((r (chi m)))
      (let ((x (ref r 0))
            (y (ref r 1))
            (z (ref r 2)))
        (chiinv (up (* x 2)
                    (* y 3) 
                    (* z 4))))))
  
  (define (mu^-1 m)
    (let ((r (chi m)))
      (let ((x (ref r 0))
            (y (ref r 1))
            (z (ref r 2)))
        (chiinv (up (/ x 2)
                    (/ y 3)
                    (/ z 4))))))
  
  (define (mu2 m)
    (let ((r (chi m)))
      (let ((x (ref r 0))
            (y (ref r 1))
            (z (ref r 2)))
        (chiinv (up (+ x y)
                    (- x y)
                    z)))))
  
  (define (mu2^-1 m)
    (let ((r (chi m)))
      (let ((x (ref r 0))
            (y (ref r 1))
            (z (ref r 2)))
        (chiinv (up (/ (+ x y) 2)
                    (/ (- x y) 2)
                    z)))))
                    
  
  (define ((close? eps) a b)
    (< (abs (- a b)) eps))
  
  (define maps-test-suite
    (test-suite
     "maps.ss"
     (test-case 
      "Pushforward under dilation."
      (check (close? 1e-6)
             ((((pushforward mu mu^-1) d/dz) z) (chiinv (up 1 2 3)))
             4))
     (test-case 
      "Pullback under dilation."
      (check (close? 1e-6)
             ((((pullback mu mu^-1) dy) d/dy) (chiinv (up 2 5 6)))
             3))
     (test-case
      "Pushforward under rotation."
      (check = ((((pushforward mu2 mu2^-1) d/dx) x) (chiinv (up 8 9 10))) 1))
     (test-case
      "Pullback under rotation"
      (check = ((((pullback mu2 mu2^-1) dy) d/dy) (chiinv (up 11 23 4))) -1)))))