http://en.wikipedia.org/wiki/Matrix_Market_exchange_formats

The Matrix Market exchange formats are a set of human readable, ASCII-based file formats designed to facilitate the exchange of matrix data. The file formats were designed and adopted for the Matrix Market, a NIST repository for test data for use in comparative studies of algorithms for numerical linear algebra。

下面是一个Matrix Market矩阵的部分截图，可以直接的理解该格式，的确是非常人性化，也方便不同软件，系统间的数据交换。

2.C#读取Matrix Market文件

　　本文还是使用Math.NET提供的程序，只不过对其结构和使用进行分析。C#读取的返回值的矩阵或者向量格式也都是Math.NET中的类型。C#读取Martix Market文件的主要类型是MatrixMarketReader，在MathNet.Numerics.Data.Text项目中，而其中的方法都是静态方法，分别为读取矩阵和读取向量，并支持从文件和流中分别读取数据。看看如下几个静态函数的原型，就可以知道怎么样了：　　

 1 public static Matrix<T> ReadMatrix<T>(string filePath,Compression compression=Compression.Uncompressed) where T : struct, IEquatable<T>, IFormattable
 2 
 3 public static Vector<T> ReadVector<T>(string filePath,Compression compression=Compression.Uncompressed) where T : struct, IEquatable<T>, IFormattable
 4 
 5 public static Matrix<T> ReadMatrix<T>(Stream stream) where T :struct,IEquatable<T>,IFormattable
 6 
 7 public static Vector<T> ReadVector<T>(Stream stream) where T :struct,IEquatable<T>,IFormattable
 8 
 9 public static Matrix<T> ReadMatrix<T>(TextReader reader) where T :struct,IEquatable<T>,IFormattable
10 
11 public static Vector<T> ReadVector<T>(TextReader reader) where T :struct,IEquatable<T>,IFormattable

　　上面要注意的是，该文件支持压缩，所以有一个Compression参数，默认是未压缩的。

3.C#保存数据为Matrix Market文件

　　C#写入Matrix Market文件的方法和上面的读取类似，使用的是MatrixMarketWriter类的静态方法，支持写入矩阵和向量，方法原型如下：

 1 public static void WriteMatrix<T>(string filePath, Matrix<T> matrix, Compression compression = Compression.Uncompressed) where T : struct, IEquatable<T>, IFormattable
 2 
 3 public static void WriteVector<T>(string filePath, Vector<T> vector, Compression compression = Compression.Uncompressed) where T : struct, IEquatable<T>, IFormattable
 4 
 5 public static void WriteMatrix<T>(Stream stream, Matrix<T> matrix) where T : struct, IEquatable<T>, IFormattable
 6 
 7 public static void WriteVector<T>(Stream stream, Vector<T> vector) where T:struct,IEquatable<T>,IFormattable
 8 
 9 public static void WriteMatrix<T>(TextWriter writer,Matrix<T> matrix) where T :struct,IEquatable<T>, IFormattable
10 
11 public static void WriteVector<T>(TextWriter writer, Vector<T> vector) where T :struct,IEquatable<T>, IFormattable