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45 #include "gromacs/legacyheaders/gmx_fatal.h"
46 #include "gromacs/legacyheaders/vec.h"
48 #include "gromacs/utility/smalloc.h"
50 #include "gmx_lapack.h"
52 double **alloc_matrix(int n, int m)
57 /* There's always time for more pointer arithmetic! */
58 /* This is necessary in order to be able to work with LAPACK */
61 for (i = 1; (i < n); i++)
68 void free_matrix(double **a)
77 void matrix_multiply(FILE *fp, int n, int m, double **x, double **y, double **z)
84 fprintf(fp, "Multiplying %d x %d matrix with a %d x %d matrix\n",
89 for (i = 0; (i < n); i++)
91 for (j = 0; (j < m); j++)
93 fprintf(fp, " %7g", x[i][j]);
99 for (i = 0; (i < m); i++)
101 for (j = 0; (j < m); j++)
104 for (k = 0; (k < n); k++)
106 z[i][j] += x[k][i]*y[j][k];
112 static void dump_matrix(FILE *fp, const char *title, int n, double **a)
117 fprintf(fp, "%s\n", title);
118 for (i = 0; (i < n); i++)
121 for (j = 0; (j < n); j++)
123 fprintf(fp, " %8.2f", a[i][j]);
127 fprintf(fp, "Prod a[i][i] = %g\n", d);
130 int matrix_invert(FILE *fp, int n, double **a)
132 int i, j, m, lda, *ipiv, lwork, info;
133 double **test = NULL, **id, *work;
138 fprintf(fp, "Inverting %d square matrix\n", n);
139 test = alloc_matrix(n, n);
140 for (i = 0; (i < n); i++)
142 for (j = 0; (j < n); j++)
144 test[i][j] = a[i][j];
147 dump_matrix(fp, "before inversion", n, a);
155 F77_FUNC(dgetrf, DGETRF) (&n, &m, a[0], &lda, ipiv, &info);
159 dump_matrix(fp, "after dgetrf", n, a);
166 F77_FUNC(dgetri, DGETRI) (&n, a[0], &lda, ipiv, work, &lwork, &info);
170 dump_matrix(fp, "after dgetri", n, a);
181 id = alloc_matrix(n, n);
182 matrix_multiply(fp, n, n, test, a, id);
183 dump_matrix(fp, "And here is the product of A and Ainv", n, id);
194 double multi_regression(FILE *fp, int nrow, double *y, int ncol,
195 double **xx, double *a0)
197 int row, niter, i, j;
198 double ax, chi2, **a, **at, **ata, *atx;
200 a = alloc_matrix(nrow, ncol);
201 at = alloc_matrix(ncol, nrow);
202 ata = alloc_matrix(ncol, ncol);
203 for (i = 0; (i < nrow); i++)
205 for (j = 0; (j < ncol); j++)
207 at[j][i] = a[i][j] = xx[j][i];
210 matrix_multiply(fp, nrow, ncol, a, at, ata);
211 if ((row = matrix_invert(fp, ncol, ata)) != 0)
213 gmx_fatal(FARGS, "Matrix inversion failed. Incorrect row = %d.\nThis probably indicates that you do not have sufficient data points, or that some parameters are linearly dependent.",
218 for (i = 0; (i < ncol); i++)
221 for (j = 0; (j < nrow); j++)
223 atx[i] += at[i][j]*y[j];
226 for (i = 0; (i < ncol); i++)
229 for (j = 0; (j < ncol); j++)
231 a0[i] += ata[i][j]*atx[j];
235 for (j = 0; (j < nrow); j++)
238 for (i = 0; (i < ncol); i++)
242 chi2 += sqr(y[j]-ax);