SparseMatrix

Full name Microsoft.VisualBasic.Math.LinearAlgebra.Matrix.SparseMatrix Assembly Microsoft.VisualBasic.Math.Core Members 7

01 Syntax

Microsoft.VisualBasic.Math.LinearAlgebra.Matrix.SparseMatrix

02 Methods

03 Properties

Name	Overloads	Summary
nnz	1	非零元素个数（即内部字典存储的 (row, col, value) 三元组数量）。

04 Fields

Name	Overloads	Summary
rows	1	just store the non-zero element index and the element value, all missing index is ZERO

05 Members

method .ctor #

#ctor(Int32, Int32)

Parameters

Name	Type	Description
`m`	`Int32`	nrows
`n`	`Int32`	ncols

method MultiplyTranspose #

MultiplyTranspose(Double())

计算转置矩阵与向量的乘积：result = Aᵀ·y

Remarks

直接遍历内部按行存储的非零元素字典完成计算，复杂度为 O(nnz)，不会将稀疏矩阵转置或稠密化。适用于随机化 SVD 等只依赖稀疏矩阵-向量乘法黑盒接口的迭代算法。

Parameters

Name	Type	Description
`y`	`Double()`	长度必须等于矩阵行数 m 的输入向量

Returns

长度为 n（列数）的结果向量

method Get #

Get(UInt32, UInt32)

Parameters

Name	Type	Description
`i`	`UInt32`	-
`j`	`UInt32`	-

Returns

value of missing index is ZERO

method ArrayPack #

ArrayPack(Boolean)

convert to real [m,n] matrix

Parameters

Name	Type	Description
`deepcopy`	`Boolean`	-

Returns

A dense matrix data

method UnpackData #

UnpackData(Single(), Int32(), Int32(), Int32)

Parameters

Name	Type	Description
`xdata`	`Single()`	-
`xindices`	`Int32()`	the corresponding index value of the xdata, this vector size of this parameter must be equals to the xdata!
`xindptr`	`Int32()`	-

property nnz #

nnz

非零元素个数（即内部字典存储的 (row, col, value) 三元组数量）。

field rows #

rows

just store the non-zero element index and the element value, all missing index is ZERO