DLASQ3(3)

💅 DLASQ3(3) — LAPACK Library Functions Manual ✨

Okay bestie, welcome to the LAPACK Library Functions Manual page for DLASQ3(3). This is the vibe: deflation checks, shift computation, and a call into dqds, all under one iconic subroutine. 🫶 main character energy, periodt.

🎀 NAME 🎀

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dlasq3.f

That path is the whole NAME moment. No cap. 💖

🌈 SYNOPSIS 🌈

🧚 Functions/Subroutines

subroutine DLASQ3 (i0, n0, z, pp, dmin, sigma, desig, qmax, nfail, iter, ndiv, ieee, ttype, dmin1, dmin2, dn, dn1, dn2, g, tau)

DLASQ3 checks for deflation, computes a shift and calls dqds. Used by sbdsqr. Slay. ✨

🔥 Function/Subroutine Documentation 🔥

subroutine DLASQ3 (integer i0, integer n0, double precision, dimension( * ) z, integer pp, double precision dmin, double precision sigma, double precision desig, double precision qmax, integer nfail, integer iter, integer ndiv, logical ieee, integer ttype, double precision dmin1, double precision dmin2, double precision dn, double precision dn1, double precision dn2, double precision g, double precision tau)

DLASQ3 checks for deflation, computes a shift and calls dqds. Used by sbdsqr. It’s giving “useful and busy.” 💅

🎯 Purpose

DLASQ3 checks for deflation, computes a shift (TAU) and calls dqds. In case of failure it changes shifts, and tries again until output is positive. So it’s lowkey persistent, bestie. 🔁✨

📋 Parameters

• I0 — I0 is INTEGER; first index. First things first.
• N0 — N0 is INTEGER; last index. Last things last.
• Z — Z is DOUBLE PRECISION array, dimension ( 4*N0 ); Z holds the qd array. Storage queen.
• PP — PP is INTEGER; PP=0 for ping, PP=1 for pong. PP=2 indicates that flipping was applied to the Z array and that the initial tests for deflation should not be performed. Ping-pong lore.
• DMIN — DMIN is DOUBLE PRECISION; minimum value of d.
• SIGMA — SIGMA is DOUBLE PRECISION; sum of shifts used in current segment.
• DESIG — DESIG is DOUBLE PRECISION; lower order part of SIGMA.
• QMAX — QMAX is DOUBLE PRECISION; maximum value of q.
• NFAIL — NFAIL is INTEGER; increment NFAIL by 1 each time the shift was too big. Oof, shift too big.
• ITER — ITER is INTEGER; increment ITER by 1 for each iteration.
• NDIV — NDIV is INTEGER; increment NDIV by 1 for each division.
• IEEE — IEEE is LOGICAL; flag for IEEE or non IEEE arithmetic (passed to DLASQ5).
• TTYPE — TTYPE is INTEGER; shift type.
• DMIN1 — DMIN1 is DOUBLE PRECISION.
• DMIN2 — DMIN2 is DOUBLE PRECISION.
• DN — DN is DOUBLE PRECISION.
• DN1 — DN1 is DOUBLE PRECISION.
• DN2 — DN2 is DOUBLE PRECISION.
• G — G is DOUBLE PRECISION.
• TAU — TAU is DOUBLE PRECISION.

DMIN1, DMIN2, DN, DN1, DN2, G, and TAU are passed as arguments in order to save their values between calls to DLASQ3. iykyk. 💜

🫶 Author

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

Definition at line 179 of file dlasq3.f. 🎀

🌸 Author (the meta one) 🌸

Generated automatically by Doxygen for LAPACK from the source code. Automated with love, fr fr. 💖

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Sign-off time, bestie: LAPACK Version 3.12.0, page path /home/abui...RC/dlasq3.f(3). That’s the footer vibe — no separate date given, and that’s the whole line. Obsessed with the transparency. 🫶✨