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authorjjesswan <jessica_wan@brown.edu>2024-04-22 21:56:26 -0400
committerjjesswan <jessica_wan@brown.edu>2024-04-22 21:56:26 -0400
commita556b45abf18f1bd509daaf63b66b7d55e9fd291 (patch)
treebc9b8a2d184c12aee236e7f9f276a34b84ca552d /engine-ocean/External/glm-master/glm/gtx/pca.inl
parentcd7c76017a12bb548036571c1ff13e551369d06d (diff)
add engine version
Diffstat (limited to 'engine-ocean/External/glm-master/glm/gtx/pca.inl')
-rw-r--r--engine-ocean/External/glm-master/glm/gtx/pca.inl343
1 files changed, 343 insertions, 0 deletions
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+/// @ref gtx_pca
+
+#ifndef GLM_HAS_CXX11_STL
+#include <algorithm>
+#else
+#include <utility>
+#endif
+
+namespace glm {
+
+
+ template<length_t D, typename T, qualifier Q>
+ GLM_INLINE mat<D, D, T, Q> computeCovarianceMatrix(vec<D, T, Q> const* v, size_t n)
+ {
+ return computeCovarianceMatrix<D, T, Q, vec<D, T, Q> const*>(v, v + n);
+ }
+
+
+ template<length_t D, typename T, qualifier Q>
+ GLM_INLINE mat<D, D, T, Q> computeCovarianceMatrix(vec<D, T, Q> const* v, size_t n, vec<D, T, Q> const& c)
+ {
+ return computeCovarianceMatrix<D, T, Q, vec<D, T, Q> const*>(v, v + n, c);
+ }
+
+
+ template<length_t D, typename T, qualifier Q, typename I>
+ GLM_FUNC_DECL mat<D, D, T, Q> computeCovarianceMatrix(I const& b, I const& e)
+ {
+ glm::mat<D, D, T, Q> m(0);
+
+ size_t cnt = 0;
+ for(I i = b; i != e; i++)
+ {
+ vec<D, T, Q> const& v = *i;
+ for(length_t x = 0; x < D; ++x)
+ for(length_t y = 0; y < D; ++y)
+ m[x][y] += static_cast<T>(v[x] * v[y]);
+ cnt++;
+ }
+ if(cnt > 0)
+ m /= static_cast<T>(cnt);
+
+ return m;
+ }
+
+
+ template<length_t D, typename T, qualifier Q, typename I>
+ GLM_FUNC_DECL mat<D, D, T, Q> computeCovarianceMatrix(I const& b, I const& e, vec<D, T, Q> const& c)
+ {
+ glm::mat<D, D, T, Q> m(0);
+ glm::vec<D, T, Q> v;
+
+ size_t cnt = 0;
+ for(I i = b; i != e; i++)
+ {
+ v = *i - c;
+ for(length_t x = 0; x < D; ++x)
+ for(length_t y = 0; y < D; ++y)
+ m[x][y] += static_cast<T>(v[x] * v[y]);
+ cnt++;
+ }
+ if(cnt > 0)
+ m /= static_cast<T>(cnt);
+
+ return m;
+ }
+
+ namespace _internal_
+ {
+
+ template<typename T>
+ GLM_INLINE T transferSign(T const& v, T const& s)
+ {
+ return ((s) >= 0 ? glm::abs(v) : -glm::abs(v));
+ }
+
+ template<typename T>
+ GLM_INLINE T pythag(T const& a, T const& b) {
+ static const T epsilon = static_cast<T>(0.0000001);
+ T absa = glm::abs(a);
+ T absb = glm::abs(b);
+ if(absa > absb) {
+ absb /= absa;
+ absb *= absb;
+ return absa * glm::sqrt(static_cast<T>(1) + absb);
+ }
+ if(glm::equal<T>(absb, 0, epsilon)) return static_cast<T>(0);
+ absa /= absb;
+ absa *= absa;
+ return absb * glm::sqrt(static_cast<T>(1) + absa);
+ }
+
+ }
+
+ template<length_t D, typename T, qualifier Q>
+ GLM_FUNC_DECL unsigned int findEigenvaluesSymReal
+ (
+ mat<D, D, T, Q> const& covarMat,
+ vec<D, T, Q>& outEigenvalues,
+ mat<D, D, T, Q>& outEigenvectors
+ )
+ {
+ using _internal_::transferSign;
+ using _internal_::pythag;
+
+ T a[D * D]; // matrix -- input and workspace for algorithm (will be changed inplace)
+ T d[D]; // diagonal elements
+ T e[D]; // off-diagonal elements
+
+ for(length_t r = 0; r < D; r++)
+ for(length_t c = 0; c < D; c++)
+ a[(r) * D + (c)] = covarMat[c][r];
+
+ // 1. Householder reduction.
+ length_t l, k, j, i;
+ T scale, hh, h, g, f;
+ static const T epsilon = static_cast<T>(0.0000001);
+
+ for(i = D; i >= 2; i--)
+ {
+ l = i - 1;
+ h = scale = 0;
+ if(l > 1)
+ {
+ for(k = 1; k <= l; k++)
+ {
+ scale += glm::abs(a[(i - 1) * D + (k - 1)]);
+ }
+ if(glm::equal<T>(scale, 0, epsilon))
+ {
+ e[i - 1] = a[(i - 1) * D + (l - 1)];
+ }
+ else
+ {
+ for(k = 1; k <= l; k++)
+ {
+ a[(i - 1) * D + (k - 1)] /= scale;
+ h += a[(i - 1) * D + (k - 1)] * a[(i - 1) * D + (k - 1)];
+ }
+ f = a[(i - 1) * D + (l - 1)];
+ g = ((f >= 0) ? -glm::sqrt(h) : glm::sqrt(h));
+ e[i - 1] = scale * g;
+ h -= f * g;
+ a[(i - 1) * D + (l - 1)] = f - g;
+ f = 0;
+ for(j = 1; j <= l; j++)
+ {
+ a[(j - 1) * D + (i - 1)] = a[(i - 1) * D + (j - 1)] / h;
+ g = 0;
+ for(k = 1; k <= j; k++)
+ {
+ g += a[(j - 1) * D + (k - 1)] * a[(i - 1) * D + (k - 1)];
+ }
+ for(k = j + 1; k <= l; k++)
+ {
+ g += a[(k - 1) * D + (j - 1)] * a[(i - 1) * D + (k - 1)];
+ }
+ e[j - 1] = g / h;
+ f += e[j - 1] * a[(i - 1) * D + (j - 1)];
+ }
+ hh = f / (h + h);
+ for(j = 1; j <= l; j++)
+ {
+ f = a[(i - 1) * D + (j - 1)];
+ e[j - 1] = g = e[j - 1] - hh * f;
+ for(k = 1; k <= j; k++)
+ {
+ a[(j - 1) * D + (k - 1)] -= (f * e[k - 1] + g * a[(i - 1) * D + (k - 1)]);
+ }
+ }
+ }
+ }
+ else
+ {
+ e[i - 1] = a[(i - 1) * D + (l - 1)];
+ }
+ d[i - 1] = h;
+ }
+ d[0] = 0;
+ e[0] = 0;
+ for(i = 1; i <= D; i++)
+ {
+ l = i - 1;
+ if(!glm::equal<T>(d[i - 1], 0, epsilon))
+ {
+ for(j = 1; j <= l; j++)
+ {
+ g = 0;
+ for(k = 1; k <= l; k++)
+ {
+ g += a[(i - 1) * D + (k - 1)] * a[(k - 1) * D + (j - 1)];
+ }
+ for(k = 1; k <= l; k++)
+ {
+ a[(k - 1) * D + (j - 1)] -= g * a[(k - 1) * D + (i - 1)];
+ }
+ }
+ }
+ d[i - 1] = a[(i - 1) * D + (i - 1)];
+ a[(i - 1) * D + (i - 1)] = 1;
+ for(j = 1; j <= l; j++)
+ {
+ a[(j - 1) * D + (i - 1)] = a[(i - 1) * D + (j - 1)] = 0;
+ }
+ }
+
+ // 2. Calculation of eigenvalues and eigenvectors (QL algorithm)
+ length_t m, iter;
+ T s, r, p, dd, c, b;
+ const length_t MAX_ITER = 30;
+
+ for(i = 2; i <= D; i++)
+ {
+ e[i - 2] = e[i - 1];
+ }
+ e[D - 1] = 0;
+
+ for(l = 1; l <= D; l++)
+ {
+ iter = 0;
+ do
+ {
+ for(m = l; m <= D - 1; m++)
+ {
+ dd = glm::abs(d[m - 1]) + glm::abs(d[m - 1 + 1]);
+ if(glm::equal<T>(glm::abs(e[m - 1]) + dd, dd, epsilon))
+ break;
+ }
+ if(m != l)
+ {
+ if(iter++ == MAX_ITER)
+ {
+ return 0; // Too many iterations in FindEigenvalues
+ }
+ g = (d[l - 1 + 1] - d[l - 1]) / (2 * e[l - 1]);
+ r = pythag<T>(g, 1);
+ g = d[m - 1] - d[l - 1] + e[l - 1] / (g + transferSign(r, g));
+ s = c = 1;
+ p = 0;
+ for(i = m - 1; i >= l; i--)
+ {
+ f = s * e[i - 1];
+ b = c * e[i - 1];
+ e[i - 1 + 1] = r = pythag(f, g);
+ if(glm::equal<T>(r, 0, epsilon))
+ {
+ d[i - 1 + 1] -= p;
+ e[m - 1] = 0;
+ break;
+ }
+ s = f / r;
+ c = g / r;
+ g = d[i - 1 + 1] - p;
+ r = (d[i - 1] - g) * s + 2 * c * b;
+ d[i - 1 + 1] = g + (p = s * r);
+ g = c * r - b;
+ for(k = 1; k <= D; k++)
+ {
+ f = a[(k - 1) * D + (i - 1 + 1)];
+ a[(k - 1) * D + (i - 1 + 1)] = s * a[(k - 1) * D + (i - 1)] + c * f;
+ a[(k - 1) * D + (i - 1)] = c * a[(k - 1) * D + (i - 1)] - s * f;
+ }
+ }
+ if(glm::equal<T>(r, 0, epsilon) && (i >= l))
+ continue;
+ d[l - 1] -= p;
+ e[l - 1] = g;
+ e[m - 1] = 0;
+ }
+ } while(m != l);
+ }
+
+ // 3. output
+ for(i = 0; i < D; i++)
+ outEigenvalues[i] = d[i];
+ for(i = 0; i < D; i++)
+ for(j = 0; j < D; j++)
+ outEigenvectors[i][j] = a[(j) * D + (i)];
+
+ return D;
+ }
+
+ template<typename T, qualifier Q>
+ GLM_INLINE void sortEigenvalues(vec<2, T, Q>& eigenvalues, mat<2, 2, T, Q>& eigenvectors)
+ {
+ if (eigenvalues[0] < eigenvalues[1])
+ {
+ std::swap(eigenvalues[0], eigenvalues[1]);
+ std::swap(eigenvectors[0], eigenvectors[1]);
+ }
+ }
+
+ template<typename T, qualifier Q>
+ GLM_INLINE void sortEigenvalues(vec<3, T, Q>& eigenvalues, mat<3, 3, T, Q>& eigenvectors)
+ {
+ if (eigenvalues[0] < eigenvalues[1])
+ {
+ std::swap(eigenvalues[0], eigenvalues[1]);
+ std::swap(eigenvectors[0], eigenvectors[1]);
+ }
+ if (eigenvalues[0] < eigenvalues[2])
+ {
+ std::swap(eigenvalues[0], eigenvalues[2]);
+ std::swap(eigenvectors[0], eigenvectors[2]);
+ }
+ if (eigenvalues[1] < eigenvalues[2])
+ {
+ std::swap(eigenvalues[1], eigenvalues[2]);
+ std::swap(eigenvectors[1], eigenvectors[2]);
+ }
+ }
+
+ template<typename T, qualifier Q>
+ GLM_INLINE void sortEigenvalues(vec<4, T, Q>& eigenvalues, mat<4, 4, T, Q>& eigenvectors)
+ {
+ if (eigenvalues[0] < eigenvalues[2])
+ {
+ std::swap(eigenvalues[0], eigenvalues[2]);
+ std::swap(eigenvectors[0], eigenvectors[2]);
+ }
+ if (eigenvalues[1] < eigenvalues[3])
+ {
+ std::swap(eigenvalues[1], eigenvalues[3]);
+ std::swap(eigenvectors[1], eigenvectors[3]);
+ }
+ if (eigenvalues[0] < eigenvalues[1])
+ {
+ std::swap(eigenvalues[0], eigenvalues[1]);
+ std::swap(eigenvectors[0], eigenvectors[1]);
+ }
+ if (eigenvalues[2] < eigenvalues[3])
+ {
+ std::swap(eigenvalues[2], eigenvalues[3]);
+ std::swap(eigenvectors[2], eigenvectors[3]);
+ }
+ if (eigenvalues[1] < eigenvalues[2])
+ {
+ std::swap(eigenvalues[1], eigenvalues[2]);
+ std::swap(eigenvectors[1], eigenvectors[2]);
+ }
+ }
+
+}//namespace glm