``ludcmpp480'' and ``lubksbp480''

void ludcmpp480(double **a, int n, int *indx, double *d);

void lubksbp480(double **a, int n, int *indx, double b[]);

Output:

• a[n][m]: LU decomposition of A (``permuted'')
• n: size of matrix
• index[n]: permutation of LU decomposition
• d: sign of determinant of A

Input:

• a[n][m]: matrix elements, A$_{nm}$
• n: size of matrix

As discussed in lecture, our new algorithm for solving large systems of non-linear equations requires us to solve small systems of linear equations of the form ${\bf G} \vec b = \vec u$. Numerical Recipes provides two routines, ``ludcmp'' and ``lubksb'', which together solve such equations. Generalize them to double precision by making the replacements ``float''$\rightarrow$``double'' and ``vector''$\rightarrow$``dvector'', and rename them with our standard p480 extension.