linear1_test.js 2.6 KB

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  1. // Copyright 2011 The Closure Library Authors. All Rights Reserved.
  2. //
  3. // Licensed under the Apache License, Version 2.0 (the "License");
  4. // you may not use this file except in compliance with the License.
  5. // You may obtain a copy of the License at
  6. //
  7. // http://www.apache.org/licenses/LICENSE-2.0
  8. //
  9. // Unless required by applicable law or agreed to in writing, software
  10. // distributed under the License is distributed on an "AS-IS" BASIS,
  11. // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12. // See the License for the specific language governing permissions and
  13. // limitations under the License.
  14. goog.provide('goog.math.interpolator.Linear1Test');
  15. goog.setTestOnly('goog.math.interpolator.Linear1Test');
  16. goog.require('goog.math.interpolator.Linear1');
  17. goog.require('goog.testing.jsunit');
  18. function testLinear() {
  19. // Test special case with no data to interpolate.
  20. var x = [];
  21. var y = [];
  22. var interp = new goog.math.interpolator.Linear1();
  23. interp.setData(x, y);
  24. assertTrue(isNaN(interp.interpolate(1)));
  25. // Test special case with 1 data point.
  26. x = [0];
  27. y = [3];
  28. interp = new goog.math.interpolator.Linear1();
  29. interp.setData(x, y);
  30. assertRoughlyEquals(3, interp.interpolate(1), 1e-4);
  31. // Test general case.
  32. x = [0, 1, 3, 6, 7];
  33. y = [0, 0, 0, 0, 0];
  34. for (var i = 0; i < x.length; ++i) {
  35. y[i] = Math.sin(x[i]);
  36. }
  37. interp = new goog.math.interpolator.Linear1();
  38. interp.setData(x, y);
  39. var xi = [0, 0.5, 1, 2, 3, 4, 5, 6, 7];
  40. var expected =
  41. [0, 0.4207, 0.8415, 0.4913, 0.1411, 0.0009, -0.1392, -0.2794, 0.657];
  42. var result = [0, 0, 0, 0, 0, 0, 0, 0, 0];
  43. for (var i = 0; i < xi.length; ++i) {
  44. result[i] = interp.interpolate(xi[i]);
  45. }
  46. assertElementsRoughlyEqual(expected, result, 1e-4);
  47. }
  48. function testOutOfBounds() {
  49. var x = [0, 1, 2];
  50. var y = [2, 5, 4];
  51. var interp = new goog.math.interpolator.Linear1();
  52. interp.setData(x, y);
  53. assertRoughlyEquals(interp.interpolate(-1), -1, 1e-4);
  54. assertRoughlyEquals(interp.interpolate(4), 2, 1e-4);
  55. }
  56. function testInverse() {
  57. var x = [0, 1, 3, 6, 7];
  58. var y = [0, 2, 7, 8, 10];
  59. var interp = new goog.math.interpolator.Linear1();
  60. interp.setData(x, y);
  61. var invInterp = interp.getInverse();
  62. var xi = [0, 0.5, 1, 2, 3, 4, 5, 6, 7];
  63. var yi = [0, 1, 2, 4.5, 7, 7.3333, 7.6667, 8, 10];
  64. var resultX = [0, 0, 0, 0, 0, 0, 0, 0, 0];
  65. var resultY = [0, 0, 0, 0, 0, 0, 0, 0, 0];
  66. for (var i = 0; i < xi.length; ++i) {
  67. resultY[i] = interp.interpolate(xi[i]);
  68. resultX[i] = invInterp.interpolate(yi[i]);
  69. }
  70. assertElementsRoughlyEqual(xi, resultX, 1e-4);
  71. assertElementsRoughlyEqual(yi, resultY, 1e-4);
  72. }