cpqr79 cpzero dka rpqr79 rpzero rpzero2

cpqr79() void cpqr79 ( int  n, doublecomplex  a[], doublecomplex  r[], doublecomplex  work[], int  lwork, int *  info  ) Roots of a polynomial (complex coefficients) (Companion matrix eigenvalues) Purpose cpqr79 computes all roots of a polynomial p(z) with complex coefficients by computing the eigenvalues of the companion matrix. 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. [out] work[] Array work[lwork] Work array. [in] lwork Size of work array. (lwork >= n*(n + 11)) [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) = -5: The argument lwork had an illegal value (lwork too small) = 1: Failed to converge QR iteration on some eigenvalue of the companion matrix Reference SLATEC