ddisna dopgtr dopmtr dorgtr dormtr dpteqr dsbtrd dsptrd dstebz dstedc dstein dstemr dsteqr dsterf dsytrd

dsterf() void dsterf ( int  n, double  d[], double  e[], int *  info  ) Eigenvalues of a symmetric tridiagonal matrix (QL or QR method) Purpose This routine computes all eigenvalues of a symmetric tridiagonal matrix using the Pal-Walker-Kahan variant of the QL or QR algorithm. Parameters [in] n Order of the matrix. (n >= 0) (If n = 0, returns without computation) [in,out] d[] Array d[ld] (ld >= n) [in] The diagonal elements of the tridiagonal matrix. [out] If info = 0, the eigenvalues in ascending order. [in,out] e[] Array e[le] (le >= n - 1) [in] The (n - 1) subdiagonal elements of the tridiagonal matrix. [out] e[] has been destroyed. [out] info = 0: Successful exit. = -1: The argument n had an illegal value. (n < 0) = i > 0: The algorithm has failed to find all of the eigenvalues in a total of 30*n iterations. i elements of e[] have not converged to zero. Reference LAPACK