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3 * This source code is part of
7 * GROningen MAchine for Chemical Simulations
10 * Written by David van der Spoel, Erik Lindahl, Berk Hess, and others.
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33 * Groningen Machine for Chemical Simulation
35 #ifndef GMX_LINEARALGEBRA_MATRIX_H
36 #define GMX_LINEARALGEBRA_MATRIX_H
45 double **alloc_matrix(int n, int m);
47 void free_matrix(double **a);
49 void matrix_multiply(FILE *fp, int n, int m, double **x, double **y, double **z);
51 /* Return 0 if OK or row number where inversion failed otherwise. */
52 int matrix_invert(FILE *fp, int n, double **a);
54 double multi_regression(FILE *fp, int ny, double *y,
55 int nx, double **xx, double *a0);
56 /* Perform a regression analysis to fit
57 * y' = a0[0] xx[0] + a0[1] xx[1] ... + a0[nx-1] xx[nx-1]
58 * with ny data points in each vector.
59 * The coefficients are returned in vector a0.
60 * The return value of the function is the chi2 value:
61 * sum_{j=0}^{ny-1} (y[j] - y'[j])^2
62 * If fp is not NULL debug information will be written to it.