/home/abui...vsy_rook.f(3)

💖 /home/abui...vsy_rook.f(3) — Library Functions Manual

🌸 NAME

• /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/zlavsy_rook.f

✨ SYNOPSIS

🧚 Functions/Subroutines

• subroutine ZLAVSY_ROOK (uplo, trans, diag, n, nrhs, a, lda, ipiv, b, ldb, info)
  • ZLAVSY_ROOK

🦋 Function/Subroutine Documentation

👑 subroutine ZLAVSY_ROOK

Here's the exact signature, bestie — no cap, this is the whole cast:

subroutine ZLAVSY_ROOK (character uplo, character trans, character diag,
    integer n, integer nrhs, complex*16, dimension( lda, * ) a, integer lda,
    integer, dimension( * ) ipiv, complex*16, dimension( ldb, * ) b, integer
    ldb, integer info)

And the subroutine's name is literally ZLAVSY_ROOK. Main character energy, honestly. 💅

💖 Purpose

ZLAVSY_ROOK performs one of the matrix-vector operations:

x := A*x  or  x := A'*x,

where x is an N element vector and A is one of the factors from the block U*D*U' or L*D*L' factorization computed by ZSYTRF_ROOK.

• If TRANS = 'N', multiplies by U or U * D (or L or L * D).
• If TRANS = 'T', multiplies by U' or D * U' (or L' or D * L').

🎀 Parameters

• UPLO — UPLO is CHARACTER*1. Specifies whether the factor stored in A is upper or lower triangular.
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• TRANS — TRANS is CHARACTER*1. Specifies the operation to be performed:
  • = 'N': x := A*x
  • = 'T': x := A'*x
• DIAG — DIAG is CHARACTER*1. Specifies whether or not the diagonal blocks are unit matrices. If the diagonal blocks are assumed to be unit, then A = U or A = L, otherwise A = U*D or A = L*D.
  • = 'U': Diagonal blocks are assumed to be unit matrices.
  • = 'N': Diagonal blocks are assumed to be non-unit matrices.
• N — N is INTEGER. The number of rows and columns of the matrix A. N >= 0.
• NRHS — NRHS is INTEGER. The number of right hand sides, i.e., the number of vectors x to be multiplied by A. NRHS >= 0.
• A — A is COMPLEX*16 array, dimension (LDA,N). The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ZSYTRF_ROOK. Stored as a 2-D triangular matrix.
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• IPIV — IPIV is INTEGER array, dimension (N). Details of the interchanges and the block structure of D, as determined by ZSYTRF_ROOK.
  • If UPLO = 'U':
    • If IPIV(k) > 0, then rows and columns k and IPIV(k) were interchanged and D(k,k) is a 1-by-1 diagonal block. (If IPIV( k ) = k, no interchange was done).
    • If IPIV(k) < 0 and IPIV(k-1) < 0, then rows and columns k and -IPIV(k) were interchanged and rows and columns k-1 and -IPIV(k-1) were interchanged, D(k-1:k,k-1:k) is a 2-by-2 diagonal block.
  • If UPLO = 'L':
    • If IPIV(k) > 0, then rows and columns k and IPIV(k) were interchanged and D(k,k) is a 1-by-1 diagonal block. (If IPIV( k ) = k, no interchange was done).
    • If IPIV(k) < 0 and IPIV(k+1) < 0, then rows and columns k and -IPIV(k) were interchanged and rows and columns k+1 and -IPIV(k+1) were interchanged, D(k:k+1,k:k+1) is a 2-by-2 diagonal block.
• B — B is COMPLEX*16 array, dimension (LDB,NRHS). On entry, B contains NRHS vectors of length N. On exit, B is overwritten with the product A * B.
• LDB — LDB is INTEGER. The leading dimension of the array B. LDB >= max(1,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 153 of file zlavsy_rook.f.

🌈 Author

Generated automatically by Doxygen for LAPACK from the source code.

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That's the whole page, bestie. Footer tea: LAPACK, Version 3.12.0, and the page tag /home/abui...vsy_rook.f(3) — and that's a wrap. 🫶💅✨