1 /*
2 * Copyright (c) 2021-2022 Huawei Device Co., Ltd.
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 */
15
16 #include "base/geometry/least_square_impl.h"
17
18 #include "base/geometry/matrix3.h"
19 #include "base/geometry/matrix4.h"
20
21 namespace OHOS::Ace {
GetLeastSquareParams(std::vector<double> & params)22 bool LeastSquareImpl::GetLeastSquareParams(std::vector<double>& params)
23 {
24 if (xVals_.size() <= 1 || ((paramsNum_ != Matrix3::DIMENSION) && (paramsNum_ != Matrix4::DIMENSION))) {
25 return false;
26 }
27 params.resize(paramsNum_, 0);
28 if (isResolved_) {
29 params.assign(params_.begin(), params_.end());
30 return true;
31 }
32 auto countNum = std::min(countNum_, static_cast<int32_t>(std::distance(xVals_.begin(), xVals_.end())));
33 std::vector<double> xVals;
34 xVals.resize(countNum, 0);
35 std::vector<double> yVals;
36 yVals.resize(countNum, 0);
37 int32_t size = countNum - 1;
38 for (auto iter = xVals_.rbegin(); iter != xVals_.rend(); iter++) {
39 xVals[size] = *iter;
40 size--;
41 if (size < 0) {
42 break;
43 }
44 }
45 size = countNum - 1;
46 for (auto iter = yVals_.rbegin(); iter != yVals_.rend(); iter++) {
47 yVals[size] = *iter;
48 size--;
49 if (size < 0) {
50 break;
51 }
52 }
53 if (paramsNum_ == Matrix3::DIMENSION) {
54 MatrixN3 matrixn3 { countNum };
55 for (auto i = 0; i < countNum; i++) {
56 const auto& value = xVals[i];
57 matrixn3[i][2] = 1;
58 matrixn3[i][1] = value;
59 matrixn3[i][0] = value * value;
60 }
61 Matrix3 invert;
62 auto transpose = matrixn3.Transpose();
63 if (!(transpose * matrixn3).Invert(invert)) {
64 return false;
65 }
66 auto matrix3n = invert * transpose;
67 auto ret = matrix3n.MapScalars(yVals, params);
68 if (ret) {
69 params_.assign(params.begin(), params.end());
70 isResolved_ = true;
71 }
72 return ret;
73 }
74 MatrixN4 matrixn4 { countNum };
75 for (auto i = 0; i < countNum; i++) {
76 const auto& value = xVals[i];
77 matrixn4[i][3] = 1;
78 matrixn4[i][2] = value;
79 matrixn4[i][1] = value * value;
80 matrixn4[i][0] = value * value * value;
81 }
82 auto transpose = matrixn4.Transpose();
83 auto inversMatrix4 = Matrix4::Invert(transpose * matrixn4);
84 auto matrix4n = inversMatrix4 * transpose;
85 auto ret = matrix4n.MapScalars(yVals, params);
86 if (ret) {
87 params_.assign(params.begin(), params.end());
88 isResolved_ = true;
89 }
90 return ret;
91 }
92 } // namespace OHOS::Ace
93