TESTING/EIG/sget34.f(3)

🦋 TESTING/EIG/sget34.f 🦋

ok so bestie, welcome to the sget34 page from the LAPACK manual — yes it's a whole file-path-looking name, don't panic, it's just how the testing directory labels itself 💅

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✨ NAME ✨

TESTING/EIG/sget34.f

like, that's literally it. that's the name. iconic of it tbh 🎀

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✨ SYNOPSIS ✨

🌸 Functions/Subroutines 🌸

• subroutine sget34 (rmax, lmax, ninfo, knt) — the one and only, SGET34 herself 👑

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💖 Function/Subroutine Documentation 💖

subroutine sget34 (real rmax, integer lmax, integer, dimension( 2 ) ninfo,
    integer knt)

SGET34 — she's the main character here, no cap ✨

🧚 Purpose 🧚

!> !> SGET34 tests SLAEXC, a routine for swapping adjacent blocks (either !> 1 by 1 or 2 by 2) on the diagonal of a matrix in real Schur form. !> Thus, SLAEXC computes an orthogonal matrix Q such that !> !> Q' * [ A B ] * Q = [ C1 B1 ] !> [ 0 C ] [ 0 A1 ] !> !> where C1 is similar to C and A1 is similar to A. Both A and C are !> assumed to be in standard form (equal diagonal entries and !> offdiagonal with differing signs) and A1 and C1 are returned with the !> same properties. !> !> The test code verifies these last last assertions, as well as that !> the residual in the above equation is small. !>

ok so real talk: SGET34 is basically running a vibe check on SLAEXC, which is the routine that swaps adjacent blocks — either 1 by 1 or 2 by 2 — sitting on the diagonal of a matrix in real Schur form. so SLAEXC builds an orthogonal matrix Q where Q' * [ A B ] * Q equals that block thing up there, with C1 being similar to C and A1 being similar to A. both A and C are assumed to be in standard form (that means equal diagonal entries and offdiagonal with differing signs, iykyk) and A1 and C1 come back with those exact same properties. 💫

then the test code goes and verifies those last last assertions (yes, the original says "last last", and honestly? she said what she said 😭), plus that the residual in the equation above is small. slay.

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🌈 Parameters 🌈

• RMAX

!> RMAX is REAL !> Value of the largest test ratio. !>

so RMAX is a REAL and it holds the value of the largest test ratio. the biggest ratio of the whole test. queen behavior 👑

• LMAX

!> LMAX is INTEGER !> Example number where largest test ratio achieved. !>

LMAX is an INTEGER — it's the example number where that largest test ratio was achieved. so when RMAX pops off, LMAX tells you which example did it 🎯

• NINFO

!> NINFO is INTEGER array, dimension (2) !> NINFO(J) is the number of examples where INFO=J occurred. !>

NINFO is an INTEGER array with dimension (2). NINFO(J) is the number of examples where INFO=J occurred — so she's keeping a lil tally for each J, very organized of her 🍓

• KNT

!> KNT is INTEGER !> Total number of examples tested. !>

KNT is an INTEGER and it's the total number of examples tested. the whole count. the receipts. periodt 💅

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👑 Author 👑

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

(that's the whole squad, credit where credit is due 🫶)

Definition at line 81 of file sget34.f. — yes, line 81, go look, she's right there ✨

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⭐ Author ⭐

Generated automatically by Doxygen for LAPACK from the source code. (so nobody hand-wrote this footer, the robot did it, and honestly? the robot ate 🤖💖)

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🎀 and that's the whole page bestie! LAPACK, Version 3.12.0, TESTING/EIG/sget34.f(3) — mwah, go test some Schur forms, ily 💜🦋