Visible to Intel only — GUID: GUID-6C1789F9-ABAC-4CC3-846C-C29A570DB9C5
Visible to Intel only — GUID: GUID-6C1789F9-ABAC-4CC3-846C-C29A570DB9C5
?gtts2
Solves a system of linear equations with a tridiagonal matrix using the LU factorization computed by ?gttrf.
Syntax
call sgtts2( itrans, n, nrhs, dl, d, du, du2, ipiv, b, ldb )
call dgtts2( itrans, n, nrhs, dl, d, du, du2, ipiv, b, ldb )
call cgtts2( itrans, n, nrhs, dl, d, du, du2, ipiv, b, ldb )
call zgtts2( itrans, n, nrhs, dl, d, du, du2, ipiv, b, ldb )
Include Files
- mkl.fi
Description
The routine solves for X one of the following systems of linear equations with multiple right hand sides:
A*X = B, AT*X = B, or AH*X = B (for complex matrices only), with a tridiagonal matrix A using the LU factorization computed by ?gttrf.
Input Parameters
- itrans
-
INTEGER. Must be 0, 1, or 2.
Indicates the form of the equations to be solved:
If itrans = 0, then A*X = B (no transpose).
If itrans = 1, then AT*X = B (transpose).
If itrans = 2, then AH*X = B (conjugate transpose).
- n
-
INTEGER. The order of the matrix A (n≥ 0).
- nrhs
-
INTEGER. The number of right-hand sides, i.e., the number of columns in B (nrhs≥ 0).
- dl,d,du,du2,b
-
REAL for sgtts2
DOUBLE PRECISION for dgtts2
COMPLEX for cgtts2
DOUBLE COMPLEX for zgtts2.
Arrays: dl(n - 1), d(n ), du(n - 1), du2(n - 2), b(ldb,nrhs).
The array dl contains the (n - 1) multipliers that define the matrix L from the LU factorization of A.
The array d contains the n diagonal elements of the upper triangular matrix U from the LU factorization of A.
The array du contains the (n - 1) elements of the first super-diagonal of U.
The array du2 contains the (n - 2) elements of the second super-diagonal of U.
The array b contains the matrix B whose columns are the right-hand sides for the systems of equations.
- ldb
-
INTEGER. The leading dimension of b; must be ldb≥ max(1, n).
- ipiv
-
INTEGER.
Array, DIMENSION (n).
The pivot indices array, as returned by ?gttrf.
Output Parameters
- b
-
Overwritten by the solution matrix X.