Documentation

The MWSparse class passes or receives a two-dimensional sparse numeric array into or from a compiled class method. This class has seven properties/methods:

Property NumRows As Long

Stores the row dimension for the array. The value of NumRows must be nonnegative. If the value is zero, the row index is taken from the maximum of the values in the RowIndex array.

Property NumColumns As Long

Stores the column dimension for the array. The value of NumColumns must be nonnegative. If the value is zero, the row index is taken from the maximum of the values in the ColumnIndex array.

Property RowIndex As Variant

Stores the array of row indices of the nonzero elements of the array. The value of this property can be any type coercible to a Variant, as well as object types, with the restriction that the underlying array must resolve to or be coercible to a numeric matrix of type Long. If the value of NumRows is nonzero and any row index is greater than NumRows, a bad-index error occurs. An error also results if the number of elements in the RowIndex array does not match the number of elements in the Array property's underlying array.

Property ColumnIndex As Variant

Stores the array of column indices of the nonzero elements of the array. The value of this property can be any type coercible to a Variant, as well as object types, with the restriction that the underlying array must resolve to or be coercible to a numeric matrix of type Long. If the value of NumColumns is nonzero and any column index is greater than NumColumns, a bad-index error occurs. An error also results if the number of elements in the ColumnIndex array does not match the number of elements in the Array property's underlying array.

Property Array As Variant

Stores the nonzero array values of the sparse array. The value of this property can be any type coercible to a Variant, as well as object types, with the restriction that the underlying array must resolve to or be coercible to a numeric matrix of type Double or Boolean.

Property MWFlags As MWFlags

Stores a reference to an MWFlags object. This property sets or gets the array formatting and data conversion flags for a particular sparse array. Each MWSparse object has its own MWFlags property. This property overrides the value of any flags set on the object whose methods are called.

Sub Clone(ppSparse As MWSparse)

Creates a copy of an MWSparse object.

Parameters

Return Value

None.

Remarks

Clone allocates a new MWSparse object and creates a deep copy of the object's contents. Call this function when a separate object is required instead of a shared copy of an existing object reference.

Example

The following Visual Basic^® sample creates a 5-by-5 tridiagonal sparse array with the following entries:

X = [ 2 -1  0   0   0
     -1  2 -1   0   0
      0 -1  2  -1   0
      0  0 -1   2  -1
      0  0  0  -1   2 ]

Sub foo()
    Dim x As MWSparse
    Dim rows(1 To 13) As Long
    Dim cols(1 To 13) As Long
    Dim vals(1 To 13) As Double
    Dim I As Long, K As Long

    On Error GoTo Handle_Error
    K = 1
    For I = 1 To 4
        rows(K) = I
        cols(K) = I + 1
        vals(K) = -1
        K = K + 1
        rows(K) = I
        cols(K) = I
        vals(K) = 2
        K = K + 1
        rows(K) = I + 1
        cols(K) = I
        vals(K) = -1
        K = K + 1
    Next
    rows(K) = 5
    cols(K) = 5
    vals(K) = 2
    Set x = New MWSparse
    x.NumRows = 5
    x.NumColumns = 5
    x.RowIndex = rows
    x.ColumnIndex = cols
    x.Array = vals
        .
        .
        .
    Exit Sub
Handle_Error:
    MsgBox (Err.Description)
End Sub