TESTING/LIN/dlattb.f(3)

📦
version 3.12.1 · 3 versions
, in arch rolling

🌸 NAME 🌸

TESTING/LIN/dlattb.f — bestie, this is the page for the dlattb subroutine, and it's coming to you from the Library Functions Manual. 💖

🦋 SYNOPSIS 🦋

🎀 Functions/Subroutines 🎀

subroutine dlattb (imat, uplo, trans, diag, iseed, n, kd, ab, ldab, b, work, info)
DLATTB

💅 Function/Subroutine Documentation 💅

subroutine dlattb (integer imat, character uplo, character trans, character diag, integer, dimension( 4 ) iseed, integer n, integer kd, double precision, dimension( ldab, * ) ab, integer ldab, double precision, dimension( * ) b, double precision, dimension( * ) work, integer info)

DLATTB is the main-character subroutine here. ✨

🎀 Purpose 🎀

okay so DLATTB generates a triangular test matrix in 2-dimensional storage. IMAT and UPLO uniquely specify the properties of the test matrix, which is returned in the array A. That's the whole purpose, and it ate. 💅

🍓 Parameters 🍓

IMAT

IMAT is INTEGER. It's an integer key describing which matrix to generate for this path. 🔑

UPLO

UPLO is CHARACTER*1. It specifies whether the matrix A will be upper or lower triangular.

  • = 'U': Upper triangular
  • = 'L': Lower triangular

TRANS

TRANS is CHARACTER*1. It specifies whether the matrix or its transpose will be used.

  • = 'N': No transpose
  • = 'T': Transpose
  • = 'C': Conjugate transpose (= transpose)

DIAG

DIAG is CHARACTER*1. It specifies whether or not the matrix A is unit triangular.

  • = 'N': Non-unit triangular
  • = 'U': Unit triangular

ISEED

ISEED is INTEGER array, dimension (4). It's the seed vector for the random number generator (used in DLATMS). Modified on exit. 🌱

N

N is INTEGER. The order of the matrix to be generated.

KD

KD is INTEGER. The number of superdiagonals or subdiagonals of the banded triangular matrix A. KD >= 0.

AB

AB is DOUBLE PRECISION array, dimension (LDAB,N). It's the upper or lower triangular banded matrix A, stored in the first KD+1 rows of AB. Let j be a column of A, 1<=j<=n.

  • If UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j.
  • If UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd).

LDAB

LDAB is INTEGER. The leading dimension of the array AB. LDAB >= KD+1.

B

B is DOUBLE PRECISION array, dimension (N).

WORK

WORK is DOUBLE PRECISION array, dimension (2*N).

INFO

INFO is INTEGER.

  • = 0: successful exit
  • < 0: if INFO = -k, the k-th argument had an illegal value

👑 Author 👑

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

Definition at line 133 of file dlattb.f.

🫶 Author 🫶

Generated automatically by Doxygen for LAPACK from the source code.

💖 footer sign-off: source/version/date line says LAPACK / Version 3.12.0 / TESTING/LIN/dlattb.f(3) — that's the very end, mwah. 💖

📦 where this page comes from