zhbtrd zhetrd zhptrd zpteqr zstedc zstein zstemr zsteqr zungtr zunmtr zupgtr zupmtr

zupgtr() void zupgtr ( char  uplo, int  n, doublecomplex  ap[], doublecomplex  tau[], int  ldq, doublecomplex  q[], doublecomplex  work[], int *  info  ) Generates a transform matrix from a complex Hermitian matrix in packed form to tridiagonal form Purpose This routine generates a complex unitary matrix Q which is defined as the product of n - 1 elementary reflectors H(i) of order n, as returned by zhptrd using packed storage. If uplo = 'U', Q = H(n-1) . . . H(2) H(1). If uplo = 'L', Q = H(1) H(2) . . . H(n-1). Parameters [in] uplo = 'U': Upper triangular packed storage used in previous call to zhptrd. = 'L': Lower triangular packed storage used in previous call to zhptrd. [in] n Order of the matrix Q. (n >= 0) (If n = 0, returns without computation) [in] ap[] Array ap[lap] (lap >= n(n + 1)/2) The vectors which define the elementary reflectors, as returned by zhptrd. [in] tau[] Array tau[ltau] (ltau >= n - 1) tau[i] must contain the scalar factor of the elementary reflector H(i), as returned by zhptrd. [in] ldq Leading dimension of the two dimensional array q[][]. (ldq >= max(1, n)) [out] q[][] Array q[lq][ldq] (lq >= n) The n x n unitary matrix Q. [out] work[] Array work[lwork] (lwork >= n - 1) Work array. [out] info = 0: Successful exit. = -1: The argument uplo had an illegal value. (uplo != 'U' nor 'L') = -2: The argument n had an illegal value. (n < 0) = -5: The argument ldq had an illegal value. (ldq < max(1, n)) Reference LAPACK