ZLATSY(3)

💅 NAME 💅

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

okay so that's the whole name, bestie — it's a Fortran file living deep in the LAPACK testing directory, and yes the path is giving "I have a very specific address and I need you to know it" 💀

(this page is from the zlatsy.f manual, section 3 — filed under Library Functions Manual, mwah 🎀)

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✨ SYNOPSIS ✨

Functions/Subroutines

subroutine ZLATSY (uplo, n, x, ldx, iseed)

ZLATSY

like... that's it. that's the whole vibe check. she's a subroutine, she's called ZLATSY, she takes uplo, n, x, ldx, and iseed, and she does not elaborate further in the synopsis 🙈

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🦋 Function/Subroutine Documentation 🦋

subroutine ZLATSY (character uplo, integer n, complex*16, dimension( ldx, * ) x, integer ldx, integer, dimension( * ) iseed)

ZLATSY 🌸

🎯 Purpose 🎯

!>
!> ZLATSY generates a special test matrix for the complex symmetric
!> (indefinite) factorization.  The pivot blocks of the generated matrix
!> will be in the following order:
!>    2x2 pivot block, non diagonalizable
!>    1x1 pivot block
!>    2x2 pivot block, diagonalizable
!>    (cycle repeats)
!> A row interchange is required for each non-diagonalizable 2x2 block.
!>

so basically she generates a special test matrix for the complex symmetric (indefinite) factorization — a little test subject, a little lab rat, if you will 🧚 and the pivot blocks of the generated matrix come out in this exact order, no cap:

1. 2x2 pivot block, non diagonalizable
2. 1x1 pivot block
3. 2x2 pivot block, diagonalizable

…and then the cycle repeats, periodt. also important, bestie: a row interchange is required for each non-diagonalizable 2x2 block 🔥 so don't forget that part, it's literally in the spec.

🌈 Parameters 🌈

• UPLO — is CHARACTER, and she decides whether the generated matrix is upper or lower triangular. the options are literally:
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• N — is INTEGER. it's the dimension of the matrix to be generated. that's the whole job description, icon behavior 👑
• X — is COMPLEX*16 array, dimension (LDX,N). this is the generated matrix itself, consisting of 3x3 and 2x2 diagonal blocks which result in the pivot sequence given above ⭐ and the matrix outside of these diagonal blocks is zero — clean, minimal, not a single extra nonzero to be found 💅
• LDX — is INTEGER. it's the leading dimension of the array X. yes she also needs to know how the array is laid out, respect the details 🫶
• ISEED — is INTEGER array, dimension (4). on entry, this is the seed for the random number generator, and the last of the four integers must be odd (!!) — and note that it's modified on exit, so don't come crying when your seed isn't the same afterward, that's just how she is 😭

👑 Author 👑

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

Definition at line 88 of file zlatsy.f. ✨

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🌸 Author 🌸

Generated automatically by Doxygen for LAPACK from the source code. so no, a human did not hand-write this little bio — the machine did it, and honestly? she ate 🤖💖

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and that's the whole page, bestie 💜 LAPACK, Version 3.12.0 — shoutout to /home/abui...IN/zlatsy.f(3) for being the source and the date of this little masterpiece. go forth and generate test matrices responsibly 🎀🌈⭐