TESTING/LIN/dtpt06.f(3)

💖 NAME 💖

Okay bestie, welcome to the TESTING/LIN/dtpt06.f(3) manual page — it's serving Library Functions Manual energy, and the actual file is TESTING/LIN/dtpt06.f ✨. The whole page is lowkey about the dtpt06 subroutine, so let's get into it 💅.

🌸 SYNOPSIS 🌸

🎀 Functions/Subroutines 🎀

subroutine dtpt06 (rcond, rcondc, uplo, diag, n, ap, work, rat)
    DTPT06

🦋 Function/Subroutine Documentation 🦋

Full signature, no cap:

subroutine dtpt06 (double precision rcond, double precision rcondc,
    character uplo, character diag, integer n, double precision, dimension(
    * ) ap, double precision, dimension( * ) work, double precision rat)
    DTPT06

💫 Purpose 💫

So DTPT06 computes a test ratio comparing RCOND (the reciprocal condition number of a triangular matrix A) and RCONDC, the estimate computed by DTPCON. Info about the triangular matrix A is used if one estimate is zero and the other is non-zero, to decide if underflow in the estimate is justified. It's giving diagnostic main character energy, honestly 🫶.

🌈 Parameters 🌈

• RCOND — RCOND is DOUBLE PRECISION. This is the estimate of the reciprocal condition number you get by forming the explicit inverse of the matrix A and computing RCOND = 1/( norm(A) * norm(inv(A)) ). Math slay 💅.
• RCONDC — RCONDC is DOUBLE PRECISION. The estimate of the reciprocal condition number computed by DTPCON.
• UPLO — UPLO is CHARACTER. Specifies whether the matrix A is upper or lower triangular.
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• DIAG — DIAG is CHARACTER. Specifies whether or not the matrix A is unit triangular.
  • = 'N': Non-unit triangular
  • = 'U': Unit triangular
• N — N is INTEGER. The order of the matrix A. N >= 0.
• AP — AP is DOUBLE PRECISION array, dimension (N*(N+1)/2). The upper or lower triangular matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows:

if UPLO = 'U', AP((j-1)*j/2 + i) = A(i,j) for 1<=i<=j;
if UPLO = 'L',
   AP((j-1)*(n-j) + j*(j+1)/2 + i-j) = A(i,j) for j<=i<=n.

Packed-array realness, iykyk 🎀.

• WORK — WORK is DOUBLE PRECISION array, dimension (N).
• RAT — RAT is DOUBLE PRECISION. The test ratio. If both RCOND and RCONDC are nonzero,

RAT = MAX( RCOND, RCONDC )/MIN( RCOND, RCONDC ) - 1.

If RAT = 0, the two estimates are exactly the same. No cap, that's the whole rule 🔥.

👑 Author 👑

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

Definition at line 110 of file dtpt06.f.

👑 Author (the auto-generated note) 👑

Generated automatically by Doxygen for LAPACK from the source code.

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And that's the vibe check, bestie 🫶 — signed off from LAPACK, Version 3.12.0, for TESTING/LIN/dtpt06.f(3) 💖. The original footer didn't show a date, so I'm not inventing one, periodt 💅.