?dttrsb

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

Download PDF

ID 766686

Date 4/28/2026

Version

Public

?dttrsb

Solves a system of linear equations with a diagonally dominant tridiagonal coefficient matrix using the LU factorization computed by ?dttrfb .

Syntax

call sdttrsb ( trans , n , nrhs , dl , d , du , b , ldb , info )

call ddttrsb ( trans , n , nrhs , dl , d , du , b , ldb , info )

call cdttrsb ( trans , n , nrhs , dl , d , du , b , ldb , info )

call zdttrsb ( trans , n , nrhs , dl , d , du , b , ldb , info )

call dttrsb ( dl , d , du , b [ , trans ] [ , info ] )

Include Files

mkl.fi , mkl_lapack.f90

Description

sdttrsb ddttrsb cdttrsb zdttrsb

The ?dttrsb routine solves the following systems of linear equations with multiple right hand sides for X :

A * X = B

if trans = ‘N’ ,

A^:code:`T` * X = B

if trans = ‘T’ ,

A^:code:`H` * X = B

if trans = ‘C’ (for complex matrices only).

Before calling this routine, call ?dttrfb (Computes the factorization of a diagonally dominant tridiagonal matrix.) to compute the factorization of A .

Input Parameters

trans

CHARACTER*1 . Must be ‘N’ or ‘T’ or ‘C’ .

Indicates the form of the equations solved for X :

If trans = 'N' , then A*X = B .

If trans = 'T' , then A^:code:`T` * X = B .

If trans = 'C' , then A^:code:`H` * X = B .

n

INTEGER . The order of A ; n ≥ 0.

nrhs

INTEGER . The number of right-hand sides, that is, the number of columns in B ; nrhs ≥ 0.

dl , d , du , b

REAL for sdttrsb

DOUBLE PRECISION for ddttrsb

COMPLEX for cdttrsb

DOUBLE COMPLEX for zdttrsb .

Arrays: dl(n -1) , d(n) , du(n -1) , b(ldb,nrhs) .

The array dl contains the (n - 1) multipliers that define the matrices L₁ , L₂ from the factorization of A .

The array d contains the n diagonal elements of the upper triangular matrix U from the factorization of A .

The array du contains the ( n - 1) elements of the superdiagonal of U .

The array b contains the matrix B whose columns are the right-hand sides for the systems of equations.

b

Array of size max(1, ldb * nrhs ). Contains the matrix B whose columns are the right-hand sides for the systems of equations.

ldb

INTEGER . The leading dimension of b ; ldb≥ max(1, n) .

Output Parameters

b

Overwritten by the solution matrix X .

info

INTEGER .

If info = 0 , the execution is successful.
If info = -i , the i -th parameter had an illegal value.

Select Your Language

Using Intel.com Search

Quick Links

Recent Searches

Advanced Search

Only search in

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

?dttrsb

Syntax

Include Files

Description

Input Parameters

Output Parameters