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37 /* This file is completely threadsafe - keep it that way! */
44 #include "gromacs/utility/fatalerror.h"
45 #include "gromacs/utility/smalloc.h"
47 static inline void do_rotate(double** a, int i, int j, int k, int l, double tau, double s)
52 a[i][j] = g - s * (h + g * tau);
53 a[k][l] = h + s * (g - h * tau);
56 void jacobi(double** a, int n, double d[], double** v, int* nrot)
60 double tresh, theta, tau, t, sm, s, h, g, c, *b, *z;
64 for (ip = 0; ip < n; ip++)
66 for (iq = 0; iq < n; iq++)
72 for (ip = 0; ip < n; ip++)
74 b[ip] = d[ip] = a[ip][ip];
78 for (i = 1; i <= 50; i++)
81 for (ip = 0; ip < n - 1; ip++)
83 for (iq = ip + 1; iq < n; iq++)
85 sm += std::abs(a[ip][iq]);
96 tresh = 0.2 * sm / (n * n);
102 for (ip = 0; ip < n - 1; ip++)
104 for (iq = ip + 1; iq < n; iq++)
106 g = 100.0 * std::abs(a[ip][iq]);
107 if (i > 4 && std::abs(d[ip]) + g == std::abs(d[ip])
108 && std::abs(d[iq]) + g == std::abs(d[iq]))
112 else if (std::abs(a[ip][iq]) > tresh)
115 if (std::abs(h) + g == std::abs(h))
121 theta = 0.5 * h / (a[ip][iq]);
122 t = 1.0 / (std::abs(theta) + std::sqrt(1.0 + theta * theta));
128 c = 1.0 / std::sqrt(1 + t * t);
137 for (j = 0; j < ip; j++)
139 do_rotate(a, j, ip, j, iq, tau, s);
141 for (j = ip + 1; j < iq; j++)
143 do_rotate(a, ip, j, j, iq, tau, s);
145 for (j = iq + 1; j < n; j++)
147 do_rotate(a, ip, j, iq, j, tau, s);
149 for (j = 0; j < n; j++)
151 do_rotate(v, j, ip, j, iq, tau, s);
157 for (ip = 0; ip < n; ip++)
164 gmx_fatal(FARGS, "Error: Too many iterations in routine JACOBI\n");
167 int m_inv_gen(real* m, int n, real* minv)
169 double **md, **v, *eig, tol, s;
170 int nzero, i, j, k, nrot;
173 for (i = 0; i < n; i++)
178 for (i = 0; i < n; i++)
183 for (i = 0; i < n; i++)
185 for (j = 0; j < n; j++)
187 md[i][j] = m[i * n + j];
192 for (i = 0; i < n; i++)
194 tol += std::abs(md[i][i]);
196 tol = 1e-6 * tol / n;
198 jacobi(md, n, eig, v, &nrot);
201 for (i = 0; i < n; i++)
203 if (std::abs(eig[i]) < tol)
210 eig[i] = 1.0 / eig[i];
214 for (i = 0; i < n; i++)
216 for (j = 0; j < n; j++)
219 for (k = 0; k < n; k++)
221 s += eig[k] * v[i][k] * v[j][k];
228 for (i = 0; i < n; i++)
233 for (i = 0; i < n; i++)