LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  dtptrs (UPLO, TRANS, DIAG, N, NRHS, AP, B, LDB, INFO) 
DTPTRS 
subroutine dtptrs  (  character  UPLO, 
character  TRANS,  
character  DIAG,  
integer  N,  
integer  NRHS,  
double precision, dimension( * )  AP,  
double precision, dimension( ldb, * )  B,  
integer  LDB,  
integer  INFO  
) 
DTPTRS
Download DTPTRS + dependencies [TGZ] [ZIP] [TXT]DTPTRS solves a triangular system of the form A * X = B or A**T * X = B, where A is a triangular matrix of order N stored in packed format, and B is an NbyNRHS matrix. A check is made to verify that A is nonsingular.
[in]  UPLO  UPLO is CHARACTER*1 = 'U': A is upper triangular; = 'L': A is lower triangular. 
[in]  TRANS  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) 
[in]  DIAG  DIAG is CHARACTER*1 = 'N': A is nonunit triangular; = 'U': A is unit triangular. 
[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]  AP  AP is DOUBLE PRECISION array, dimension (N*(N+1)/2) The upper or lower triangular matrix A, packed columnwise in a linear array. The jth column of A is stored in the array AP as follows: if UPLO = 'U', AP(i + (j1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j1)*(2*nj)/2) = A(i,j) for j<=i<=n. 
[in,out]  B  B is DOUBLE PRECISION array, dimension (LDB,NRHS) On entry, the right hand side matrix B. On exit, if INFO = 0, the 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, the ith diagonal element of A is zero, indicating that the matrix is singular and the solutions X have not been computed. 
Definition at line 131 of file dtptrs.f.