GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 4.8 |
i386 |
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cpttrs(l) |
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CPTTRS - solve a tridiagonal system of the form A * X = B using the factorization A = U’*D*U or A = L*D*L’ computed by CPTTRF
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SUBROUTINE CPTTRS( |
UPLO, N, NRHS, D, E, B, LDB, INFO ) |
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CHARACTER |
UPLO |
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INTEGER |
INFO, LDB, N, NRHS |
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REAL |
D( * ) |
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COMPLEX |
B( LDB, * ), E( * ) |
CPTTRS solves a tridiagonal system of the form A * X = B using the factorization A = U’*D*U or A = L*D*L’ computed by CPTTRF. D is a diagonal matrix specified in the vector D, U (or L) is a unit bidiagonal matrix whose superdiagonal (subdiagonal) is specified in the vector E, and X and B are N by NRHS matrices.
UPLO (input) CHARACTER*1
Specifies the form of the
factorization and whether the vector E is the superdiagonal
of the upper bidiagonal factor U or the subdiagonal of the
lower bidiagonal factor L. = ’U’: A =
U’*D*U, E is the superdiagonal of U
= ’L’: A = L*D*L’, E is the subdiagonal of
L
N (input) INTEGER
The order of the tridiagonal matrix A. N >= 0.
NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
D (input) REAL array, dimension (N)
The n diagonal elements of the diagonal matrix D from the factorization A = U’*D*U or A = L*D*L’.
E (input) COMPLEX array, dimension (N-1)
If UPLO = ’U’, the (n-1) superdiagonal elements of the unit bidiagonal factor U from the factorization A = U’*D*U. If UPLO = ’L’, the (n-1) subdiagonal elements of the unit bidiagonal factor L from the factorization A = L*D*L’.
B (input/output) REAL array, dimension (LDB,NRHS)
On entry, the right hand side vectors B for the system of linear equations. On exit, the solution vectors, X.
LDB (input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal
value
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cpttrs(l) | |