Linear Algebra Operations Extensions.Band Multiply And Add In Place Method
Definition
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 9.0.3
Overload List
Band | Performs one of the matrix-vector operations y := alpha*A*x + beta*y, or y := alpha*AT*x + beta*y, where alpha and beta are scalars, x and y are vectors and A is an m by n band matrix, with kl sub-diagonals and ku super-diagonals. |
Band | Sum of the product of a general band matrix and vector and a scaled vector. |
BandMultiplyAndAddInPlace<T>(ILinearAlgebraOperations<T>, TransposeOperation, Int32, Int32, Int32, Int32, T, ReadOnlySpan2D<T>, ReadOnlySpanSlice<T>, T, SpanSlice<T>)
Performs one of the matrix-vector operations y := alpha*A*x + beta*y, or y := alpha*AT*x + beta*y, where alpha and beta are scalars, x and y are vectors and A is an m by n band matrix, with kl sub-diagonals and ku super-diagonals.
public static void BandMultiplyAndAddInPlace<T>(
this ILinearAlgebraOperations<T> operations,
TransposeOperation trans,
int m,
int n,
int kl,
int ku,
T alpha,
ReadOnlySpan2D<T> a,
ReadOnlySpanSlice<T> x,
T beta,
SpanSlice<T> y
)
Parameters
- operations ILinearAlgebraOperations<T>
- The object that performs the operation.
- trans TransposeOperation
On entry, TRANS specifies the operation to be performed as follows: TRANS = 'N' or 'n' y := alpha*A*x + beta*y. TRANS = 'T' or 't' y := alpha*AT*x + beta*y. TRANS = 'C' or 'c' y := alpha*AT*x + beta*y.
- m Int32
On entry, M specifies the number of rows of the matrix A. M must be at least zero.
- n Int32
On entry, N specifies the number of columns of the matrix A. N must be at least zero.
- kl Int32
On entry, KL specifies the number of sub-diagonals of the matrix A. KL must satisfy 0 .le. KL.
- ku Int32
On entry, KU specifies the number of super-diagonals of the matrix A. KU must satisfy 0 .le. KU.
- alpha T
ALPHA is DOUBLE PRECISION. On entry, ALPHA specifies the scalar alpha.
- a ReadOnlySpan2D<T>
A is DOUBLE PRECISION array of DIMENSION ( LDA, n ). Before entry, the leading ( kl + ku + 1 ) by n part of the array A must contain the matrix of coefficients, supplied column by column, with the leading diagonal of the matrix in row ( ku + 1 ) of the array, the first super-diagonal starting at position 2 in row ku, the first sub-diagonal starting at position 1 in row ( ku + 2 ), and so on. Elements in the array A that do not correspond to elements in the band matrix (such as the top left ku by ku triangle) are not referenced. The following program segment will transfer a band matrix from conventional full matrix storage to band storage: DO 20, J = 1, N K = KU + 1 - J DO 10, I = MAX( 1, J - KU ), MIN( M, J + KL ) A( K + I, J ) = matrix( I, J ) 10 CONTINUE 20 CONTINUE
On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least ( kl + ku + 1 ).
- x ReadOnlySpanSlice<T>
X is DOUBLE PRECISION array of DIMENSION at least ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( m - 1 )*abs( INCX ) ) otherwise. Before entry, the incremented array X must contain the vector x.
On entry, INCX specifies the increment for the elements of X. INCX must not be zero.
- beta T
BETA is DOUBLE PRECISION. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input.
- y SpanSlice<T>
Y is DOUBLE PRECISION array of DIMENSION at least ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. Before entry, the incremented array Y must contain the vector y. On exit, Y is overwritten by the updated vector y.
On entry, INCY specifies the increment for the elements of Y. INCY 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
Further Details:
Level 2 LinearAlgebra routine. The vector and matrix arguments are not referenced when N = 0, or M = 0 -- 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
BandMultiplyAndAddInPlace<T, TStorage, TStorage2D>(ILinearAlgebraOperations<T>, TransposeOperation, Int32, Int32, Int32, Int32, T, TStorage2D, TStorage, T, TStorage)
public static void BandMultiplyAndAddInPlace<T, TStorage, TStorage2D>(
this ILinearAlgebraOperations<T> operations,
TransposeOperation transposeOperation,
int m,
int n,
int kl,
int ku,
T alpha,
TStorage2D a,
TStorage x,
T beta,
TStorage y
)
where TStorage : Object, IStorageSlice<T>
where TStorage2D : Object, IStorage2D<T>
Parameters
- operations ILinearAlgebraOperations<T>
- The linear algebra operations instance used to perform the calculation.
- transposeOperation TransposeOperation
- Specifies the operation to be performed on the matrix a.
- m Int32
- The number of rows in the matrix a.
- n Int32
- The number of columns in the matrix a.
- kl Int32
- The lower bandwidth of the matrix a.
- ku Int32
- The upper bandwidth of the matrix a.
- alpha T
- The scalar used to multiply the matrix-vector product.
- 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.
- beta T
- The scalar used to multiply y.
- y TStorage
- A reference to a one-dimensional array containing the elements of the vector y. The elements of y 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 DGBMV.