.TH "SRC/sla_gbrcond.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/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 "\fBSLA_GBRCOND\fP estimates the Skeel condition number for a general banded matrix\&. " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "real function sla_gbrcond (character trans, integer n, integer kl, integer ku, real, dimension( ldab, * ) ab, integer ldab, real, dimension( ldafb, * ) afb, integer ldafb, integer, dimension( * ) ipiv, integer cmode, real, dimension( * ) c, integer info, 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 .PP Definition at line \fB166\fP of file \fBsla_gbrcond\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.