SRC/dla_lin_berr.f(3)

🎀 SRC/dla_lin_berr.f(3) 🎀

Library Functions Manual — yes bestie, that’s the manual name folded in near the top like a little header accessory 💅

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✨ NAME ✨

SRC/dla_lin_berr.f — literally the page name, no cap. 🫶

🦋 SYNOPSIS 🦋

💖 Functions/Subroutines 💖

• subroutine dla_lin_berr (n, nz, nrhs, res, ayb, berr) — DLA_LIN_BERR computes a component-wise relative backward error. 🔥

🌸 Function/Subroutine Documentation 🌸

   subroutine dla_lin_berr (integer n, integer nz, integer nrhs, double
       precision, dimension( n, nrhs ) res, double precision, dimension( n,
       nrhs ) ayb, double precision, dimension( nrhs ) berr)

DLA_LIN_BERR computes a component-wise relative backward error. ✨

🧚 Purpose 🧚

The formula is sacred, so here it is exactly, bestie:

!>
!>    DLA_LIN_BERR computes component-wise relative backward error from
!>    the formula
!>        max(i) ( abs(R(i)) / ( abs(op(A_s))*abs(Y) + abs(B_s) )(i) )
!>    where abs(Z) is the component-wise absolute value of the matrix
!>    or vector Z.
!>

💅 Parameters 💅

• N — N is INTEGER: the number of linear equations, i.e. the order of matrix A. N >= 0. 🫶
• NZ — NZ is INTEGER: we add (NZ+1)*SLAMCH( 'Safe minimum' ) to R(i) in the numerator to guard against spuriously zero residuals. Default value is N. 😭💖
• NRHS — NRHS is INTEGER: the number of right hand sides, i.e. the number of columns of the matrices AYB, RES, and BERR. NRHS >= 0. ✨
• RES — RES is DOUBLE PRECISION array, dimension (N,NRHS): the residual matrix, i.e. the matrix R in the relative backward error formula above. 🔥
• AYB — AYB is DOUBLE PRECISION array, dimension (N, NRHS): the denominator in the relative backward error formula above, i.e. the matrix abs(op(A_s))*abs(Y) + abs(B_s). The matrices A, Y, and B are from iterative refinement (see dla_gerfsx_extended.f). 🎀
• BERR — BERR is DOUBLE PRECISION array, dimension (NRHS): the component-wise relative backward error from the formula above. 👑

👑 Author 👑

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

Definition at line 100 of file dla_lin_berr.f. 💖

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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Okay byeee bestie — footer check: LAPACK Version 3.12.0, source SRC/dla_lin_berr.f(3), and that’s the source/version + date footer energy, periodt 💅✨