CGBBRD(3)

💖 NAME 💖

CGBBRD(3) from the Library Functions Manual has entered the chat, bestie. The file it documents is /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/cgbbrd.f.

🌈 SYNOPSIS 🌈

🧩 Functions/Subroutines 🧩

subroutine CGBBRD (vect, m, n, ncc, kl, ku, ab, ldab, d, e, q, ldq, pt,
    ldpt, c, ldc, work, rwork, info)
    CGBBRD

🦋 Function/Subroutine Documentation 🦋

subroutine CGBBRD (character vect, integer m, integer n, integer ncc,
    integer kl, integer ku, complex, dimension( ldab, * ) ab, integer ldab,
    real, dimension( * ) d, real, dimension( * ) e, complex, dimension( ldq,
    * ) q, integer ldq, complex, dimension( ldpt, * ) pt, integer ldpt,
    complex, dimension( ldc, * ) c, integer ldc, complex, dimension( * )
    work, real, dimension( * ) rwork, integer info)
    CGBBRD

🎯 Purpose 🎯

CGBBRD reduces a complex general m-by-n 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.

🌸 Parameters 🌸

• VECT — VECT is CHARACTER*1. It 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 array, dimension (LDAB,N). On entry, the m-by-n band matrix A, stored in rows 1 to KL+KU+1. The j-th column of A is stored in the j-th column of the array AB as follows: AB(ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=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 REAL array, dimension (min(M,N)). The diagonal elements of the bidiagonal matrix B.
• E — E is REAL array, dimension (min(M,N)-1). The superdiagonal elements of the bidiagonal matrix B.
• Q — Q is COMPLEX array, dimension (LDQ,M). If VECT = 'Q' or 'B', the m-by-m 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 array, dimension (LDPT,N). If VECT = 'P' or 'B', the n-by-n 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 array, dimension (LDC,NCC). On entry, an m-by-ncc 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 array, dimension (max(M,N)).
• RWORK — RWORK is REAL array, dimension (max(M,N)).
• INFO — INFO is INTEGER. = 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value.

👑 Author 👑

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 191 of file cgbbrd.f.

🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

💌 cute sign-off, bestie: source/version is LAPACK Version 3.12.0; the footer path is /home/abui...RC/cgbbrd.f(3); date: not listed in the original footer, so I’m not inventing one, ngl. Periodt. 💅