CTBT06(3)

📦 version 3.12.0, in opensuse-leap 16.0

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/ctbt06.f

okay so bestie, this is the manpage for /home/abui...IN/ctbt06.f(3), and it’s hanging out in the Library Functions Manual section 3. iconic. 💅

✨ SYNOPSIS ✨

💖 Functions/Subroutines 💖

subroutine CTBT06 (rcond, rcondc, uplo, diag, n, kd, ab, ldab, rwork, rat)
    CTBT06

🦋 Function/Subroutine Documentation 🦋

subroutine CTBT06 (real rcond, real rcondc, character uplo, character diag, integer n, integer kd, complex, dimension( ldab, * ) ab, integer ldab, real, dimension( * ) rwork, real rat)
    CTBT06

🌈 Purpose 🌈

CTBT06 computes a test ratio comparing RCOND — the reciprocal condition number of a triangular matrix A — and RCONDC, the estimate computed by CTBCON. Information about the triangular matrix A is used if one estimate is zero and the other is non-zero, so it can decide if underflow in the estimate is justified. 🫶

🎀 Parameters 🎀

RCOND

RCOND is REAL. It’s the estimate of the reciprocal condition number obtained by forming the explicit inverse of the matrix A and computing:

RCOND = 1/( norm(A) * norm(inv(A)) ).

RCONDC

RCONDC is REAL. It’s the estimate of the reciprocal condition number computed by CTBCON.

UPLO

UPLO is CHARACTER. It specifies whether the matrix A is upper or lower triangular:

  • = 'U': Upper triangular
  • = 'L': Lower triangular

DIAG

DIAG is CHARACTER. It specifies whether or not the matrix A is unit triangular:

  • = 'N': Non-unit triangular
  • = 'U': Unit triangular

N

N is INTEGER. It’s the order of the matrix A. N >= 0.

KD

KD is INTEGER. It’s the number of superdiagonals or subdiagonals of the triangular band matrix A. KD >= 0.

AB

AB is COMPLEX array, dimension (LDAB,N). It’s the upper or lower triangular band matrix A, stored in the first kd+1 rows of the array. The j-th column of A is stored in the j-th column of the array AB as follows:

if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j;
if UPLO = 'L', AB(1+i-j,j)    = A(i,j) for j<=i<=min(n,j+kd).

LDAB

LDAB is INTEGER. It’s the leading dimension of the array AB. LDAB >= KD+1.

RWORK

RWORK is REAL array, dimension (N).

RAT

RAT is REAL. It’s 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. ✨

👑 Author 👑

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

Definition at line 124 of file ctbt06.f.

🤖 Author 🤖

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later bestie! 💋 this page is rockin’ LAPACK Version 3.12.0, and the footer path is /home/abui...IN/ctbt06.f(3). slay and read the docs. 🫶🎀

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