GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 4.8 |
i386 |
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slaqtr(l) |
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SLAQTR - solve the real quasi-triangular system op(T)*p = scale*c, if LREAL = .TRUE
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SUBROUTINE SLAQTR( |
LTRAN, LREAL, N, T, LDT, B, W, SCALE, X, WORK, INFO ) | ||
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LOGICAL |
LREAL, LTRAN | ||
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INTEGER |
INFO, LDT, N | ||
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REAL |
SCALE, W | ||
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REAL |
B( * ), T( LDT, * ), WORK( * ), X( * ) |
SLAQTR solves the real quasi-triangular system op(T)*p = scale*c, if LREAL = .TRUE. or the complex quasi-triangular systems
op(T + iB)*(p+iq) = scale*(c+id), if LREAL = .FALSE.
in real
arithmetic, where T is upper quasi-triangular.
If LREAL = .FALSE., then the first diagonal block of T must
be 1 by 1, B is the specially structured matrix
B = [ b(1) b(2)
... b(n) ]
[ w ]
[ w ]
[ . ]
[ w ]
op(A) = A or
A’, A’ denotes the conjugate transpose of
matrix A.
On input, X = [
c ]. On output, X = [ p ].
[ d ] [ q ]
This subroutine is designed for the condition number estimation in routine STRSNA.
LTRAN (input) LOGICAL
On entry, LTRAN specifies the option of conjugate transpose: = .FALSE., op(T+i*B) = T+i*B, = .TRUE., op(T+i*B) = (T+i*B)’.
LREAL (input) LOGICAL
On entry, LREAL specifies the input matrix structure: = .FALSE., the input is complex = .TRUE., the input is real
N (input) INTEGER
On entry, N specifies the order of T+i*B. N >= 0.
T (input) REAL array, dimension (LDT,N)
On entry, T contains a matrix in Schur canonical form. If LREAL = .FALSE., then the first diagonal block of T must be 1 by 1.
LDT (input) INTEGER
The leading dimension of the matrix T. LDT >= max(1,N).
B (input) REAL array, dimension (N)
On entry, B contains the elements to form the matrix B as described above. If LREAL = .TRUE., B is not referenced.
W (input) REAL
On entry, W is the diagonal element of the matrix B. If LREAL = .TRUE., W is not referenced.
SCALE (output) REAL
On exit, SCALE is the scale factor.
X (input/output) REAL array, dimension (2*N)
On entry, X contains the right hand side of the system. On exit, X is overwritten by the solution.
WORK (workspace) REAL array,
dimension (N)
INFO (output) INTEGER
On exit, INFO is set to 0:
successful exit.
1: the some diagonal 1 by 1 block has been perturbed by a
small number SMIN to keep nonsingularity. 2: the some
diagonal 2 by 2 block has been perturbed by a small number
in SLALN2 to keep nonsingularity. NOTE: In the interests of
speed, this routine does not check the inputs for
errors.
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slaqtr(l) | |