DLA_SYRCOND
Purpose
DLA_SYRCOND 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.
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.
Arguments
| UPLO |
(input) CHARACTER*1
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored. |
| N |
(input) INTEGER
The number of linear equations, i.e., the order of the
matrix A. N >= 0. |
| A |
(input) DOUBLE PRECISION array, dimension (LDA,N)
On entry, the N-by-N matrix A.
|
| LDA |
(input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
|
| AF |
(input) DOUBLE PRECISION array, dimension (LDAF,N)
The block diagonal matrix D and the multipliers used to
obtain the factor U or L as computed by DSYTRF. |
| LDAF |
(input) INTEGER
The leading dimension of the array AF. LDAF >= max(1,N).
|
| IPIV |
(input) INTEGER array, dimension (N)
Details of the interchanges and the block structure of D
as determined by DSYTRF. |
| CMODE |
(input) 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)
|
| C |
(input) DOUBLE PRECISION array, dimension (N)
The vector C in the formula op(A) * op2(C).
|
| INFO |
(output) INTEGER
= 0: Successful exit.
i > 0: The ith argument is invalid. |
| WORK |
(input) DOUBLE PRECISION array, dimension (3*N).
Workspace.
|
| IWORK |
(input) INTEGER array, dimension (N).
Workspace.
|