Linear Algebra Operations Extensions.Band Triangular Solve In Place Method
Definition
Namespace: Numerics.NET.Collections
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 9.0.2
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 9.0.2
Overload List
Band | Solves one of the systems of equations A*x = b, or AT*x = b, where b and x are n element vectors and A is an n by n unit, or non-unit, upper or lower triangular band matrix, with ( k + 1 ) diagonals. |
Band | Solves a triangular band system of equations. |
BandTriangularSolveInPlace<T>(ILinearAlgebraOperations<T>, MatrixTriangle, TransposeOperation, MatrixDiagonal, Int32, Int32, ReadOnlySpan2D<T>, SpanSlice<T>)
Solves one of the systems of equations A*x = b, or AT*x = b, where b and x are n element vectors and A is an n by n unit, or non-unit, upper or lower triangular band matrix, with ( k + 1 ) diagonals.
public static void BandTriangularSolveInPlace<T>(
this ILinearAlgebraOperations<T> operations,
MatrixTriangle uplo,
TransposeOperation trans,
MatrixDiagonal diag,
int n,
int k,
ReadOnlySpan2D<T> a,
SpanSlice<T> x
)
Parameters
- operations ILinearAlgebraOperations<T>
- The object that performs the operation.
- uplo MatrixTriangle
On entry, UPLO specifies whether the matrix is an upper or lower triangular matrix as follows: UPLO = 'U' or 'u' A is an upper triangular matrix. UPLO = 'L' or 'l' A is a lower triangular matrix.
- trans TransposeOperation
On entry, TRANS specifies the equations to be solved as follows: TRANS = 'N' or 'n' A*x = b. TRANS = 'T' or 't' AT*x = b. TRANS = 'C' or 'c' AT*x = b.
- diag MatrixDiagonal
On entry, DIAG specifies whether or not A is unit triangular as follows: DIAG = 'U' or 'u' A is assumed to be unit triangular. DIAG = 'N' or 'n' A is not assumed to be unit triangular.
- n Int32
On entry, N specifies the order of the matrix A. N must be at least zero.
- k Int32
On entry with UPLO = 'U' or 'u', K specifies the number of super-diagonals of the matrix A. On entry with UPLO = 'L' or 'l', K specifies the number of sub-diagonals of the matrix A. K must satisfy 0 .le. K.
- a ReadOnlySpan2D<T>
A is DOUBLE PRECISION array of DIMENSION ( LDA, n ). Before entry with UPLO = 'U' or 'u', the leading ( k + 1 ) by n part of the array A must contain the upper triangular band part of the matrix of coefficients, supplied column by column, with the leading diagonal of the matrix in row ( k + 1 ) of the array, the first super-diagonal starting at position 2 in row k, and so on. The top left k by k triangle of the array A is not referenced. The following program segment will transfer an upper triangular band matrix from conventional full matrix storage to band storage: DO 20, J = 1, N M = K + 1 - J DO 10, I = MAX( 1, J - K ), J A( M + I, J ) = matrix( I, J ) 10 CONTINUE 20 CONTINUE Before entry with UPLO = 'L' or 'l', the leading ( k + 1 ) by n part of the array A must contain the lower triangular band part of the matrix of coefficients, supplied column by column, with the leading diagonal of the matrix in row 1 of the array, the first sub-diagonal starting at position 1 in row 2, and so on. The bottom right k by k triangle of the array A is not referenced. The following program segment will transfer a lower triangular band matrix from conventional full matrix storage to band storage: DO 20, J = 1, N M = 1 - J DO 10, I = J, MIN( N, J + K ) A( M + I, J ) = matrix( I, J ) 10 CONTINUE 20 CONTINUE Note that when DIAG = 'U' or 'u' the elements of the array A corresponding to the diagonal elements of the matrix are not referenced, but are assumed to be unity.
On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least ( k + 1 ).
- x SpanSlice<T>
X is DOUBLE PRECISION array of dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the n element right-hand side vector b. On exit, X is overwritten with the solution vector x.
On entry, INCX specifies the increment for the elements of X. INCX must not be zero.
Type Parameters
- T
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type ILinearAlgebraOperations<T>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).Remarks
No test for singularity or near-singularity is included in this routine. Such tests must be performed before calling this routine.
Further Details:
Level 2 LinearAlgebra routine. -- Written on 22-October-1986. Jack Dongarra, Argonne National Lab. Jeremy Du Croz, Nag Central Office. Sven Hammarling, Nag Central Office. Richard Hanson, Sandia National Labs.
Authors: Univ. of Tennessee, Univ. of California Berkeley, Univ. of Colorado Denver, NAG Ltd.
Date: November 2011
BandTriangularSolveInPlace<T, TStorage, TStorage2D>(ILinearAlgebraOperations<T>, MatrixTriangle, TransposeOperation, MatrixDiagonal, Int32, Int32, TStorage2D, TStorage)
Solves a triangular band system of equations.
public static void BandTriangularSolveInPlace<T, TStorage, TStorage2D>(
this ILinearAlgebraOperations<T> operations,
MatrixTriangle storedTriangle,
TransposeOperation transposeOperation,
MatrixDiagonal diagonal,
int n,
int k,
TStorage2D a,
TStorage x
)
where TStorage : Object, IStorageSlice<T>
where TStorage2D : Object, IStorage2D<T>
Parameters
- operations ILinearAlgebraOperations<T>
- The linear algebra operations instance used to perform the calculation.
- storedTriangle MatrixTriangle
- Specifies whether the matrix is an upper or lower triangular matrix.
- transposeOperation TransposeOperation
- Specifies the operation to be performed on the matrix a.
- diagonal MatrixDiagonal
- Specifies whether or not a is unit triangular.
- n Int32
- The number of rows and columns in the matrix a.
- k Int32
- The bandwidth of the matrix a.
- a TStorage2D
- A span that contains the elements of the matrix.
- x TStorage
- A reference to a one-dimensional array containing the elements of the vector x. The elements of x are overwritten with the result.
Type Parameters
- T
- TStorage
- TStorage2D
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type ILinearAlgebraOperations<T>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).Remarks
This method is similar to the BLAS routine DTBSV.