?dttrf

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 4/28/2026

Version

Public

?dttrf

Computes an LU factorization of a general tridiagonal matrix with no pivoting (local blocked algorithm).

Syntax

voidsdttrf ( MKL_INT*n , float*dl , float*d , float*du , MKL_INT*info );

voidddttrf ( MKL_INT*n , double*dl , double*d , double*du , MKL_INT*info );

voidcdttrf ( MKL_INT*n , MKL_Complex8*dl , MKL_Complex8*d , MKL_Complex8*du , MKL_INT*info );

voidzdttrf ( MKL_INT*n , MKL_Complex16*dl , MKL_Complex16*d , MKL_Complex16*du , MKL_INT*info );

Include Files

mkl_scalapack.h

Description

sdttrf ddttrf cdttrf zdttrf The ?dttrf routine function computes an LU factorization of a real or complex tridiagonal matrix A using elimination without partial pivoting.

The factorization has the form A = L*U , where L is a product of unit lower bidiagonal matrices and U is upper triangular with nonzeros only in the main diagonal and first superdiagonal.

Input Parameters

n

The order of the matrix A(n ≥ 0) .

dl , d , du: REAL for sdttrf DOUBLE PRECISION for ddttrf COMPLEX for cdttrf COMPLEX*16 for zdttrf . Arrays containing elements of A . The array dl of size (n-1) contains the sub-diagonal elements of A . The array d of size n contains the diagonal elements of A . The array du of size (n-1) contains the super-diagonal elements of A .

Output Parameters

dl: Overwritten by the (n-1) multipliers that define the matrix L from the LU factorization of A .
d: Overwritten by the n diagonal elements of the upper triangular matrix U from the LU factorization of A .
du: Overwritten by the (n-1) elements of the first super-diagonal of U .

info

= 0: successful exit < 0: if info = - i , the i -th argument had an illegal value,

> 0: if info = i , the matrix element U ( i , i ) is exactly 0. The factorization has been completed, but the factor U is exactly singular. Division by 0 will occur if you use the factor U for solving a system of linear equations.

NOTE:

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Developer Reference for Intel® oneAPI Math Kernel Library for C

?dttrf

Syntax

Include Files

Description

Input Parameters

Output Parameters