ZLAED0(3)

okay bestie, welcome to the zlaed0.f(3) page from the Library Functions Manual — this is ZLAED0(3) and it’s giving numerical linear algebra excellence, lowkey iconic 💅✨

🎀 NAME 🎀

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zlaed0.f

that’s the file path, no cap 🫶

🌸 SYNOPSIS 🌸

✨ Functions/Subroutines ✨

       subroutine ZLAED0 (qsiz, n, d, e, q, ldq, qstore, ldqs, rwork, iwork,
           info)

ZLAED0 is used by ZSTEDC. It computes all eigenvalues and corresponding eigenvectors of an unreduced symmetric tridiagonal matrix using the divide and conquer method. slay.

💫 Function/Subroutine Documentation 💫

   subroutine ZLAED0 (integer qsiz, integer n, double precision, dimension( * )
       d, double precision, dimension( * ) e, complex*16, dimension( ldq, * )
       q, integer ldq, complex*16, dimension( ldqs, * ) qstore, integer ldqs,
       double precision, dimension( * ) rwork, integer, dimension( * ) iwork,
       integer info)

ZLAED0 is used by ZSTEDC. It computes all eigenvalues and corresponding eigenvectors of an unreduced symmetric tridiagonal matrix using the divide and conquer method. yes she said it twice — the docs said it twice too, so we’re keeping the energy 💖

🎯 Purpose 🎯

Using the divide and conquer method, ZLAED0 computes all eigenvalues of a symmetric tridiagonal matrix — and that matrix is one diagonal block of those from reducing a dense or band Hermitian matrix — plus the corresponding eigenvectors of the dense or band matrix. periodt ✨

🌈 Parameters 🌈

• QSIZ — QSIZ is INTEGER. The dimension of the unitary matrix used to reduce the full matrix to tridiagonal form. QSIZ >= N if ICOMPQ = 1. 💅
• N — N is INTEGER. The dimension of the symmetric tridiagonal matrix. N >= 0. 🌸
• D — D is DOUBLE PRECISION array, dimension (N). On entry, the diagonal elements of the tridiagonal matrix. On exit, the eigenvalues in ascending order. 🎀
• E — E is DOUBLE PRECISION array, dimension (N-1). On entry, the off-diagonal elements of the tridiagonal matrix. On exit, E has been destroyed. 💀
• Q — Q is COMPLEX*16 array, dimension (LDQ,N). On entry, Q must contain an QSIZ x N matrix whose columns unitarily orthonormal. It is a part of the unitary matrix that reduces the full dense Hermitian matrix to a (reducible) symmetric tridiagonal matrix. 🦋
• LDQ — LDQ is INTEGER. The leading dimension of the array Q. LDQ >= max(1,N). ✨
• IWORK — IWORK is INTEGER array. The dimension of IWORK must be at least 6 + 6*N + 5*N*lg N where ( lg( N ) = smallest integer k such that 2^k >= N ). 👑
• RWORK — RWORK is DOUBLE PRECISION array, dimension (1 + 3*N + 2*N*lg N + 3*N**2) where ( lg( N ) = smallest integer k such that 2^k >= N ). 🔥
• QSTORE — QSTORE is COMPLEX*16 array, dimension (LDQS, N). Used to store parts of the eigenvector matrix when the updating matrix multiplies take place. 🍓
• LDQS — LDQS is INTEGER. The leading dimension of the array QSTORE. LDQS >= max(1,N). 🧚
• INFO — INFO is INTEGER. The values are:
  • = 0: successful exit. ✅
  • < 0: if INFO = -i, the i-th argument had an illegal value. 🙈
  • > 0: The algorithm failed to compute an eigenvalue while working on the submatrix lying in rows and columns INFO/(N+1) through mod(INFO,N+1). 💀

💖 Author 💖

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

Definition at line 143 of file zlaed0.f.

🌟 Author 🌟

Generated automatically by Doxygen for LAPACK from the source code. (Not me, bestie — Doxygen did that 💀)

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okay that’s the whole page, bestie. This one is from LAPACK Version 3.12.0, and the footer path is /home/abui...RC/zlaed0.f(3). mwah 💋💖