ZLA_LIN_BERR(3)

🎀 NAME 🎀

Bestie, this is the zla_lin_berr.f(3) page from the Library Functions Manual, and the path it's repping is:

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

---

✨ SYNOPSIS ✨

Functions/Subroutines

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

---

🦋 Function/Subroutine Documentation 🦋

Okay so here's the whole signature, copied exactly because we do not play with code:

subroutine ZLA_LIN_BERR (integer n, integer nz, integer nrhs, complex*16,
     dimension( n, nrhs ) res, double precision, dimension( n, nrhs ) ayb,
     double precision, dimension( nrhs ) berr)

ZLA_LIN_BERR computes a component-wise relative backward error. Iconic, honestly.

🌸 Purpose 🌸

ZLA_LIN_BERR computes componentwise 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 componentwise absolute value of the matrix or vector Z.

💖 Parameters 💖

N

N is INTEGER. The number of linear equations, i.e., the order of the 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 COMPLEX*16 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 zla_gerfsx_extended.f).

BERR

BERR is DOUBLE PRECISION array, dimension (NRHS). The componentwise 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 zla_lin_berr.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

---

Okay bestie, that's the whole page. The footer says LAPACK Version 3.12.0 and /home/abui..._lin_berr.f(3); there's no date in it, so I'm not inventing one. Periodt. 💅✨