
NAMEzgbbrd.f SYNOPSISFunctions/Subroutinessubroutine zgbbrd (VECT, M, N, NCC, KL, KU, AB, LDAB, D, E, Q, LDQ, PT, LDPT, C, LDC, WORK, RWORK, INFO) Function/Subroutine Documentationsubroutine zgbbrd (characterVECT, integerM, integerN, integerNCC, integerKL, integerKU, complex*16, dimension( ldab, * )AB, integerLDAB, double precision, dimension( * )D, double precision, dimension( * )E, complex*16, dimension( ldq, * )Q, integerLDQ, complex*16, dimension( ldpt, * )PT, integerLDPT, complex*16, dimension( ldc, * )C, integerLDC, complex*16, dimension( * )WORK, double precision, dimension( * )RWORK, integerINFO)ZGBBRD Purpose:ZGBBRD reduces a complex general mbyn band matrix A to real upper bidiagonal form B by a unitary transformation: Q**H * A * P = B. The routine computes B, and optionally forms Q or P**H, or computes Q**H*C for a given matrix C. VECT
Author:
VECT is CHARACTER*1 Specifies whether or not the matrices Q and P**H are to be formed. = 'N': do not form Q or P**H; = 'Q': form Q only; = 'P': form P**H only; = 'B': form both.M M is INTEGER The number of rows of the matrix A. M >= 0.N N is INTEGER The number of columns of the matrix A. N >= 0.NCC NCC is INTEGER The number of columns of the matrix C. NCC >= 0.KL KL is INTEGER The number of subdiagonals of the matrix A. KL >= 0.KU KU is INTEGER The number of superdiagonals of the matrix A. KU >= 0.AB AB is COMPLEX*16 array, dimension (LDAB,N) On entry, the mbyn band matrix A, stored in rows 1 to KL+KU+1. The jth column of A is stored in the jth column of the array AB as follows: AB(ku+1+ij,j) = A(i,j) for max(1,jku)<=i<=min(m,j+kl). On exit, A is overwritten by values generated during the reduction.LDAB LDAB is INTEGER The leading dimension of the array A. LDAB >= KL+KU+1.D D is DOUBLE PRECISION array, dimension (min(M,N)) The diagonal elements of the bidiagonal matrix B.E E is DOUBLE PRECISION array, dimension (min(M,N)1) The superdiagonal elements of the bidiagonal matrix B.Q Q is COMPLEX*16 array, dimension (LDQ,M) If VECT = 'Q' or 'B', the mbym unitary matrix Q. If VECT = 'N' or 'P', the array Q is not referenced.LDQ LDQ is INTEGER The leading dimension of the array Q. LDQ >= max(1,M) if VECT = 'Q' or 'B'; LDQ >= 1 otherwise.PT PT is COMPLEX*16 array, dimension (LDPT,N) If VECT = 'P' or 'B', the nbyn unitary matrix P'. If VECT = 'N' or 'Q', the array PT is not referenced.LDPT LDPT is INTEGER The leading dimension of the array PT. LDPT >= max(1,N) if VECT = 'P' or 'B'; LDPT >= 1 otherwise.C C is COMPLEX*16 array, dimension (LDC,NCC) On entry, an mbyncc matrix C. On exit, C is overwritten by Q**H*C. C is not referenced if NCC = 0.LDC LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M) if NCC > 0; LDC >= 1 if NCC = 0.WORK WORK is COMPLEX*16 array, dimension (max(M,N))RWORK RWORK is DOUBLE PRECISION array, dimension (max(M,N))INFO INFO is INTEGER = 0: successful exit. < 0: if INFO = i, the ith argument had an illegal value. Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
Definition at line 193 of file zgbbrd.f.
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