LAPACK
3.5.0
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  dgtsv (N, NRHS, DL, D, DU, B, LDB, INFO) 
DGTSV computes the solution to system of linear equations A * X = B for GT matrices More...  
subroutine dgtsv  (  integer  N, 
integer  NRHS,  
double precision, dimension( * )  DL,  
double precision, dimension( * )  D,  
double precision, dimension( * )  DU,  
double precision, dimension( ldb, * )  B,  
integer  LDB,  
integer  INFO  
) 
DGTSV computes the solution to system of linear equations A * X = B for GT matrices
Download DGTSV + dependencies [TGZ] [ZIP] [TXT]DGTSV solves the equation A*X = B, where A is an n by n tridiagonal matrix, by Gaussian elimination with partial pivoting. Note that the equation A**T*X = B may be solved by interchanging the order of the arguments DU and DL.
[in]  N  N is INTEGER The order of the matrix A. N >= 0. 
[in]  NRHS  NRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0. 
[in,out]  DL  DL is DOUBLE PRECISION array, dimension (N1) On entry, DL must contain the (n1) subdiagonal elements of A. On exit, DL is overwritten by the (n2) elements of the second superdiagonal of the upper triangular matrix U from the LU factorization of A, in DL(1), ..., DL(n2). 
[in,out]  D  D is DOUBLE PRECISION array, dimension (N) On entry, D must contain the diagonal elements of A. On exit, D is overwritten by the n diagonal elements of U. 
[in,out]  DU  DU is DOUBLE PRECISION array, dimension (N1) On entry, DU must contain the (n1) superdiagonal elements of A. On exit, DU is overwritten by the (n1) elements of the first superdiagonal of U. 
[in,out]  B  B is DOUBLE PRECISION array, dimension (LDB,NRHS) On entry, the N by NRHS matrix of right hand side matrix B. On exit, if INFO = 0, the N by NRHS solution matrix X. 
[in]  LDB  LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N). 
[out]  INFO  INFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value > 0: if INFO = i, U(i,i) is exactly zero, and the solution has not been computed. The factorization has not been completed unless i = N. 
Definition at line 128 of file dgtsv.f.