Recipe 6.31. Creating a Matrix


Problem

You want to declare a matrix, populate it with nonzero values, and perform several standard matrix calculations on it.

Solution

Sample code folder: Chapter 06\Matrix

This recipe demonstrates how to declare and populate a matrix in a clear, readable way. A module of matrix functions is also included, although several of the functions it contains will be presented in follow-up recipes.

Discussion

Nested braces containing comma-separated numbers can be used to fill arrays of one or more dimensions. In the case of a two-dimensional matrix, the braces can optionally be separated to show each row of numbers on its own line using the underscore (_) line-continuation character. Feel free to use whatever layout details work for you, but the following sample of a 3 x 3 matrix can provide a decent, visually appealing layout in your source code:

 Dim matrixA(,) As Double = { _    {4, 5, 6}, _    {7, 8, 9}, _    {3, 2, 1}} MsgBox(MatrixHelper.MakeDisplayable(matrixA)) 

The last line of this code uses a function named MakeDisplayable() to return a string representation of a matrix suitable for display, as shown in Figure 6-31. This function is one of several to be presented in the code module named MatrixHelper.

Figure 6-31. The custom output of the matrix


The MatrixHelper module contains several functions to work with matrices, and the recipes that follow will describe them further. A complete listing of MatrixHelper.vb can be found at the end of this chapter.

See Also

See the full MatrixHelper.vb listing in Recipe 6.35.




Visual Basic 2005 Cookbook(c) Solutions for VB 2005 Programmers
Visual Basic 2005 Cookbook: Solutions for VB 2005 Programmers (Cookbooks (OReilly))
ISBN: 0596101775
EAN: 2147483647
Year: 2006
Pages: 400

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