Generic Decomposition Operations<T>.Band Triangular Solve Method
Solves a triangular system of the form A * X = B or AT * X = B, where A is a triangular band matrix of order N, and B is an N-by NRHS matrix.
Definition
Namespace: Extreme.Mathematics.LinearAlgebra.Implementation
Assembly: Extreme.Numerics.Generic (in Extreme.Numerics.Generic.dll) Version: 8.1.4
C#
Assembly: Extreme.Numerics.Generic (in Extreme.Numerics.Generic.dll) Version: 8.1.4
public override void BandTriangularSolve(
MatrixTriangle storedTriangle,
TransposeOperation trans,
MatrixDiagonal diag,
int n,
int kd,
int nrhs,
Array2D<T> ab,
Array2D<T> b,
out int info
)
Parameters
- storedTriangle MatrixTriangle
= 'U': A is upper triangular; = 'L': A is lower triangular.
- trans TransposeOperation
Specifies the form the system of equations: = 'N': A * X = B (No transpose) = 'T': AT * X = B (Transpose) = 'C': AH * X = B (Conjugate transpose = Transpose)
- diag MatrixDiagonal
= 'N': A is non-unit triangular; = 'U': A is unit triangular.
- n Int32
The order of the matrix A. N >= 0.
- kd Int32
The number of superdiagonals or subdiagonals of the triangular band matrix A. KD >= 0.
- nrhs Int32
The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
- ab Array2D<T>
Dimension (LDAB,N) The upper or lower triangular band matrix A, stored in the first kd+1 rows of AB. The j-th column of A is stored in the j-th column of the array AB as follows: if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j; if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd). If DIAG = 'U', the diagonal elements of A are not referenced and are assumed to be 1.
The leading dimension of the array AB. LDAB >= KD+1.
- b Array2D<T>
Dimension (LDB,NRHS) On entry, the right hand side matrix B. On exit, if info = 0, the solution matrix X.
The leading dimension of the array B. LDB >= max(1,N).
- info Int32
info is INTEGER = 0: successful exit < 0: if info = -i, the i-th argument had an illegal value > 0: if info = i, the i-th diagonal element of A is zero, indicating that the matrix is singular and the solutions X have not been computed.
Remarks
A check is made to verify that A is nonsingular.
This method corresponds to the LAPACK routine DTBTRS.