#| SO31-test.ss: Test suite for the SO31.ss module. 
Copyright (C) 2007 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 SO31-test mzscheme
  (require "SO31.ss"
           (planet "all.ss" ("wmfarr" "plt-linalg.plt" 1 1))
           (planet "test.ss" ("schematics" "schemeunit.plt" 2))
           (lib "42.ss" "srfi")
           (planet "srfi-4-comprehensions.ss" ("wmfarr" "srfi-4-comprehensions.plt")))
  
  (provide SO31-test-suite)
  
  (define (check-matrix-close? eps m1 m2)
    (every?-ec (:parallel (:matrix x1 m1)
                          (:matrix x2 m2))
      (< (abs (- x1 x2)) (abs eps))))
  
  (define (check-second-order? a b)
    (let ((ratio (abs (/ a b))))
      (or (and (> ratio 3.9)
               (< ratio 4.1))
          (and (> ratio 0.45)
               (< ratio 0.55)))))
  
  (define eta (matrix 4 4
                      -1 0 0 0
                      0 1 0 0
                      0 0 1 0
                      0 0 0 1))
  
  (define (eta-transform M)
    (matrix-mul (matrix-mul (matrix-transpose M)
                            eta)
                M))
  
  (define (random-param)
    (- (random) 0.5))
  
  (define (random-params)
    (f64vector-of-length-ec 6 (:range i 6) (random-param)))
  
  (define (M-+-dM M dps dMs)
    (fold-ec M (:parallel (:f64vector dp dps)
                          (:vector dM dMs))
      (matrix-scale dM dp)
      (lambda (dM M-acc)
        (matrix-add dM M-acc))))
  
  (define SO31-test-suite
    (test-suite
     "SO31.ss test suite"
     (test-case
      "Each of the individual matrices preserves eta"
      (do-ec (:list M (list Rx Ry Rz Bx By Bz))
        (let* ((p (random-param))
               (M (M p)))
          (check-matrix-close? 1e-10 eta (eta-transform M)))))
     (test-case
      "Full LT Matrix Preserves eta"
      (do-ec (:range i 6)
        (let* ((p (random-params))
               (M (params->matrix p)))
          (check-matrix-close? 1e-10 eta (eta-transform M)))))
     (test-case
      "matrix->params and params->matrix are inverses"
      (do-ec (:range i 6)
        (let* ((p (random-params))
               (M (params->matrix p))
               (p2 (matrix->params M))
               (M2 (params->matrix p2)))
          (check-matrix-close? 1e-10 M M2))))
     (test-case
      "derivative gives linear approximation to increment"
      (do-ec (:range i 6)
        (let* ((eps 1e-6)
               (p0 (random-params))
               (p-inc (random-params))
               (dp1 (f64vector-scale p-inc eps))
               (dp2 (f64vector-scale p-inc (/ eps 2)))
               (p1 (f64vector-add dp1 p0))
               (p2 (f64vector-add dp2 p0))
               (M0 (params->matrix p0))
               (M1 (params->matrix p1))
               (M2 (params->matrix p2))
               (dMs-matrix (matrix->dM M0))
               (dMs-params (params->dM p0))
               (approx-M1-matrix (M-+-dM M0 dp1 dMs-matrix))
               (approx-M2-matrix (M-+-dM M0 dp2 dMs-matrix))
               (approx-M1-params (M-+-dM M0 dp1 dMs-params))
               (approx-M2-params (M-+-dM M0 dp2 dMs-params))
               (e1-matrix (matrix-norm (matrix-sub approx-M1-matrix M1)))
               (e2-matrix (matrix-norm (matrix-sub approx-M2-matrix M2)))
               (e1-params (matrix-norm (matrix-sub approx-M1-params M1)))
               (e2-params (matrix-norm (matrix-sub approx-M2-params M2))))
          (check-second-order? e1-matrix e2-matrix)
          (check-second-order? e1-params e2-params)))))))