cpqr79 cpzero dka rpqr79 rpzero rpzero2

dka() void dka ( int  n, doublecomplex  a[], doublecomplex  r[], int  maxiter, int *  iter, doublecomplex  work[], double  rwork[], int *  info  ) Roots of a polynomial (complex coefficients) (3rd order DKA method) Purpose dka computes all roots of a polynomial p(z) with complex coefficients by 3rd order DKA (Durand-Kerner-Aberth) method. p(z) = a0*z^n + a1*z^(n-1) + ... + an Parameters [in] n Degree of polynomial. (n >= 1) [in] a[] Array a[la] (la >= n + 1) Complex coefficient vector of p(z) (a0 to an). [out] r[] Array r[lr] (lr >= n) The obtained zeros. [in] maxiter Maximum number of iterations. (maxiter >= 1) [out] iter Number of iterations required to converge. [out] work[] Array work[lwork] (lwork >= n + 1) Work array. [out] rwork[] Array rwork[lrwork] (lrwork >= n + 1) Work array. [out] info = 0: Successful exit = -1: The argument n had an illegal value (n < 1) = -2: The argument a had an illegal value (a[0] = 0) = -4: The argument maxiter had an illegal value (maxiter <= 0) = 1: Failed to converge after maxiter iterations Reference (Japanese book) Masatake Mori "FORTRAN77 Numerical Calculation Programming (augmented edition)" Iwanami Shoten (1987)