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

💖 bestie, you're reading /home/abui...nvf_rook.f(3) from the Library Functions Manual — manual name folded in near the top, exactly as requested, and we're about to make SSYCONVF_ROOK make sense. 💖

✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/ssyconvf_rook.f

🦋 SYNOPSIS 🦋

🌸 Functions/Subroutines 🌸

• subroutine SSYCONVF_ROOK (uplo, way, n, a, lda, e, ipiv, info) — that's the one, bestie. SSYCONVF_ROOK.

💅 Function/Subroutine Documentation 💅

subroutine SSYCONVF_ROOK (character uplo, character way, integer n, real,
     dimension( lda, * ) a, integer lda, real, dimension( * ) e, integer,
     dimension( * ) ipiv, integer info)

SSYCONVF_ROOK

🎯 Purpose

Okay so, if parameter WAY = 'C': SSYCONVF_ROOK converts the factorization output format used in SSYTRF_ROOK provided on entry in parameter A into the factorization output format used in SSYTRF_RK (or SSYTRF_BK) that is stored on exit in parameters A and E. The IPIV format for SSYTRF_ROOK and SSYTRF_RK (or SSYTRF_BK) is the same and is not converted. Periodt. 💅

If parameter WAY = 'R': SSYCONVF_ROOK performs the conversion in reverse direction, i.e. converts the factorization output format used in SSYTRF_RK (or SSYTRF_BK) provided on entry in parameters A and E into the factorization output format used in SSYTRF_ROOK that is stored on exit in parameter A. The IPIV format for SSYTRF_ROOK and SSYTRF_RK (or SSYTRF_BK) is the same and is not converted. Slay. ✨

🧚 Parameters

💜 UPLO

UPLO is CHARACTER*1. It specifies whether the details of the factorization are stored as an upper or lower triangular matrix A.

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

💜 WAY

WAY is CHARACTER*1.

• = 'C': Convert
• = 'R': Revert

💜 N

N is INTEGER. The order of the matrix A. N >= 0.

💜 A

A is REAL array, dimension (LDA,N).

1. If WAY = 'C':
   • On entry, contains factorization details in format used in SSYTRF_ROOK:
     • a) all elements of the symmetric block diagonal matrix D on the diagonal of A and on superdiagonal (or subdiagonal) of A, and
     • b) If UPLO = 'U': multipliers used to obtain factor U in the superdiagonal part of A. If UPLO = 'L': multipliers used to obtain factor L in the superdiagonal part of A.
   • On exit, contains factorization details in format used in SSYTRF_RK or SSYTRF_BK:
     • a) ONLY diagonal elements of the symmetric block diagonal matrix D on the diagonal of A, i.e. D(k,k) = A(k,k); (superdiagonal (or subdiagonal) elements of D are stored on exit in array E), and
     • b) If UPLO = 'U': factor U in the superdiagonal part of A. If UPLO = 'L': factor L in the subdiagonal part of A.
2. If WAY = 'R':
   • On entry, contains factorization details in format used in SSYTRF_RK or SSYTRF_BK:
     • a) ONLY diagonal elements of the symmetric block diagonal matrix D on the diagonal of A, i.e. D(k,k) = A(k,k); (superdiagonal (or subdiagonal) elements of D are stored on exit in array E), and
     • b) If UPLO = 'U': factor U in the superdiagonal part of A. If UPLO = 'L': factor L in the subdiagonal part of A.
   • On exit, contains factorization details in format used in SSYTRF_ROOK:
     • a) all elements of the symmetric block diagonal matrix D on the diagonal of A and on superdiagonal (or subdiagonal) of A, and
     • b) If UPLO = 'U': multipliers used to obtain factor U in the superdiagonal part of A. If UPLO = 'L': multipliers used to obtain factor L in the superdiagonal part of A.

💜 LDA

LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).

💜 E

E is REAL array, dimension (N).

1. If WAY = 'C':
   • On entry, just a workspace.
   • On exit, contains the superdiagonal (or subdiagonal) elements of the symmetric block diagonal matrix D with 1-by-1 or 2-by-2 diagonal blocks, where:
     • If UPLO = 'U': E(i) = D(i-1,i), i=2:N, E(1) is set to 0;
     • If UPLO = 'L': E(i) = D(i+1,i), i=1:N-1, E(N) is set to 0.
2. If WAY = 'R':
   • On entry, contains the superdiagonal (or subdiagonal) elements of the symmetric block diagonal matrix D with 1-by-1 or 2-by-2 diagonal blocks, where:
     • If UPLO = 'U': E(i) = D(i-1,i),i=2:N, E(1) not referenced;
     • If UPLO = 'L': E(i) = D(i+1,i),i=1:N-1, E(N) not referenced.
   • On exit, is not changed.

💜 IPIV

IPIV is INTEGER array, dimension (N). On entry, details of the interchanges and the block structure of D as determined:

1. by SSYTRF_ROOK, if WAY = 'C';
2. by SSYTRF_RK (or SSYTRF_BK), if WAY = 'R'.

The IPIV format is the same for all these routines.

On exit, is not changed.

💜 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.

🌈 Contributors

November 2017, Igor Kozachenko, Computer Science Division, University of California, Berkeley

🎀 Definition at line

Definition at line 196 of file ssyconvf_rook.f.

💀 Author

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