DSYGST(3)

🎀 NAME 🎀

okay bestie, this is the DSYGST(3) page from the Library Functions Manual 💅 and the name/path on the page is literally:

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

✨ SYNOPSIS ✨

Functions/Subroutines

• subroutine DSYGST (itype, uplo, n, a, lda, b, ldb, info)
• DSYGST

🦋 Function/Subroutine Documentation 🦋

subroutine DSYGST (integer itype, character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldb, * ) b, integer ldb, integer info)
DSYGST

💖 Purpose 💖

okay so the DSYGST routine reduces a real symmetric-definite generalized eigenproblem to standard form. Iconic behavior, no notes.

• If ITYPE = 1, the problem is A*x = lambda*B*x, and A is overwritten by inv(U**T)*A*inv(U) or inv(L)*A*inv(L**T).
• If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or B*A*x = lambda*x, and A is overwritten by U*A*U**T or L**T*A*L.
• B must have been previously factorized as U**T*U or L*L**T by DPOTRF.

🌸 Parameters 🌸

• ITYPE — ITYPE is INTEGER; = 1: compute inv(U**T)*A*inv(U) or inv(L)*A*inv(L**T); = 2 or 3: compute U*A*U**T or L**T*A*L.
• UPLO — UPLO is CHARACTER*1; = 'U': Upper triangle of A is stored and B is factored as U**T*U; = 'L': Lower triangle of A is stored and B is factored as L*L**T.
• N — N is INTEGER; the order of the matrices A and B. N >= 0.
• A — A is DOUBLE PRECISION array, dimension (LDA,N). On entry, the symmetric matrix A. If UPLO = 'U', the leading N-by-N upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading N-by-N lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if INFO = 0, the transformed matrix, stored in the same format as A.
• LDA — LDA is INTEGER; the leading dimension of the array A. LDA >= max(1,N).
• B — B is DOUBLE PRECISION array, dimension (LDB,N); the triangular factor from the Cholesky factorization of B, as returned by DPOTRF.
• 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 = -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 126 of file dsygst.f.

📝 Author 📝

Generated automatically by Doxygen for LAPACK from the source code.

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okay that’s the whole page, bestie 💖 — the footer info is LAPACK Version 3.12.0, and the page file is at /home/abui...RC/dsygst.f(3). mwah 💋