.TH "sla_gbrcond.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME sla_gbrcond.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "real function \fBsla_gbrcond\fP (TRANS, N, KL, KU, AB, LDAB, AFB, LDAFB, IPIV, CMODE, C, INFO, WORK, IWORK)" .br .RI "\fI\fBSLA_GBRCOND\fP estimates the Skeel condition number for a general banded matrix\&. \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "real function sla_gbrcond (characterTRANS, integerN, integerKL, integerKU, real, dimension( ldab, * )AB, integerLDAB, real, dimension( ldafb, * )AFB, integerLDAFB, integer, dimension( * )IPIV, integerCMODE, real, dimension( * )C, integerINFO, real, dimension( * )WORK, integer, dimension( * )IWORK)" .PP \fBSLA_GBRCOND\fP estimates the Skeel condition number for a general banded matrix\&. .PP \fBPurpose: \fP .RS 4 .PP .nf SLA_GBRCOND Estimates the Skeel condition number of op(A) * op2(C) where op2 is determined by CMODE as follows CMODE = 1 op2(C) = C CMODE = 0 op2(C) = I CMODE = -1 op2(C) = inv(C) The Skeel condition number cond(A) = norminf( |inv(A)||A| ) is computed by computing scaling factors R such that diag(R)*A*op2(C) is row equilibrated and computing the standard infinity-norm condition number. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fITRANS\fP .PP .nf TRANS is CHARACTER*1 Specifies the form of the system of equations: = 'N': A * X = B (No transpose) = 'T': A**T * X = B (Transpose) = 'C': A**H * X = B (Conjugate Transpose = Transpose) .fi .PP .br \fIN\fP .PP .nf N is INTEGER The number of linear equations, i.e., the order of the matrix A. N >= 0. .fi .PP .br \fIKL\fP .PP .nf KL is INTEGER The number of subdiagonals within the band of A. KL >= 0. .fi .PP .br \fIKU\fP .PP .nf KU is INTEGER The number of superdiagonals within the band of A. KU >= 0. .fi .PP .br \fIAB\fP .PP .nf AB is REAL array, dimension (LDAB,N) On entry, the matrix A in band storage, in rows 1 to KL+KU+1. The j-th column of A is stored in the j-th column of the array AB as follows: AB(KU+1+i-j,j) = A(i,j) for max(1,j-KU)<=i<=min(N,j+kl) .fi .PP .br \fILDAB\fP .PP .nf LDAB is INTEGER The leading dimension of the array AB. LDAB >= KL+KU+1. .fi .PP .br \fIAFB\fP .PP .nf AFB is REAL array, dimension (LDAFB,N) Details of the LU factorization of the band matrix A, as computed by SGBTRF. U is stored as an upper triangular band matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and the multipliers used during the factorization are stored in rows KL+KU+2 to 2*KL+KU+1. .fi .PP .br \fILDAFB\fP .PP .nf LDAFB is INTEGER The leading dimension of the array AFB. LDAFB >= 2*KL+KU+1. .fi .PP .br \fIIPIV\fP .PP .nf IPIV is INTEGER array, dimension (N) The pivot indices from the factorization A = P*L*U as computed by SGBTRF; row i of the matrix was interchanged with row IPIV(i). .fi .PP .br \fICMODE\fP .PP .nf CMODE is INTEGER Determines op2(C) in the formula op(A) * op2(C) as follows: CMODE = 1 op2(C) = C CMODE = 0 op2(C) = I CMODE = -1 op2(C) = inv(C) .fi .PP .br \fIC\fP .PP .nf C is REAL array, dimension (N) The vector C in the formula op(A) * op2(C). .fi .PP .br \fIINFO\fP .PP .nf INFO is INTEGER = 0: Successful exit. i > 0: The ith argument is invalid. .fi .PP .br \fIWORK\fP .PP .nf WORK is REAL array, dimension (5*N). Workspace. .fi .PP .br \fIIWORK\fP .PP .nf IWORK is INTEGER array, dimension (N). Workspace. .fi .PP .RE .PP \fBAuthor:\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP \fBDate:\fP .RS 4 September 2012 .RE .PP .PP Definition at line 168 of file sla_gbrcond\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.