1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "suggest/core/layout/normal_distribution_2d.h" 18 19 #include <gtest/gtest.h> 20 21 #include <vector> 22 23 namespace latinime { 24 namespace { 25 26 static const float ORIGIN_X = 0.0f; 27 static const float ORIGIN_Y = 0.0f; 28 static const float LARGE_STANDARD_DEVIATION = 100.0f; 29 static const float SMALL_STANDARD_DEVIATION = 10.0f; 30 static const float ZERO_RADIAN = 0.0f; 31 32 TEST(NormalDistribution2DTest, ProbabilityDensity) { 33 const NormalDistribution2D distribution(ORIGIN_X, LARGE_STANDARD_DEVIATION, ORIGIN_Y, 34 SMALL_STANDARD_DEVIATION, ZERO_RADIAN); 35 36 static const float SMALL_COORDINATE = 10.0f; 37 static const float LARGE_COORDINATE = 20.0f; 38 // The probability density of the point near the distribution center is larger than the 39 // probability density of the point that is far from distribution center. 40 EXPECT_GE(distribution.getProbabilityDensity(SMALL_COORDINATE, SMALL_COORDINATE), 41 distribution.getProbabilityDensity(LARGE_COORDINATE, LARGE_COORDINATE)); 42 // The probability density of the point shifted toward the direction that has larger standard 43 // deviation is larger than the probability density of the point shifted towards another 44 // direction. 45 EXPECT_GE(distribution.getProbabilityDensity(LARGE_COORDINATE, SMALL_COORDINATE), 46 distribution.getProbabilityDensity(SMALL_COORDINATE, LARGE_COORDINATE)); 47 } 48 49 TEST(NormalDistribution2DTest, Rotate) { 50 static const float COORDINATES[] = {0.0f, 10.0f, 100.0f, -20.0f}; 51 static const float EPSILON = 0.01f; 52 const NormalDistribution2D distribution(ORIGIN_X, LARGE_STANDARD_DEVIATION, ORIGIN_Y, 53 SMALL_STANDARD_DEVIATION, ZERO_RADIAN); 54 const NormalDistribution2D rotatedDistribution(ORIGIN_X, LARGE_STANDARD_DEVIATION, ORIGIN_Y, 55 SMALL_STANDARD_DEVIATION, M_PI_4); 56 for (const float x : COORDINATES) { 57 for (const float y : COORDINATES) { 58 // The probability density of the rotated distribution at the point and the probability 59 // density of the original distribution at the rotated point are the same. 60 const float probabilityDensity0 = distribution.getProbabilityDensity(x, y); 61 const float probabilityDensity1 = rotatedDistribution.getProbabilityDensity(-y, x); 62 EXPECT_NEAR(probabilityDensity0, probabilityDensity1, EPSILON); 63 } 64 } 65 } 66 67 } // namespace 68 } // namespace latinime 69