forked from tsai/mathnet-numerics
Christoph Ruegg
12 years ago
4 changed files with 165 additions and 10 deletions
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(*** hide ***) |
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#I "../../out/lib/net40" |
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#r "MathNet.Numerics.dll" |
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#r "MathNet.Numerics.FSharp.dll" |
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(** |
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MATLAB Level-5 Mat Files |
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======================== |
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Level-5 MATLAB Mat files are popular as binary file container for storing one or more matrices. |
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Math.NET Numerics provides basic support for such Mat files with the **MathNet.Numerics.Data.Matlab** package, |
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which is available on NuGet as separate package and not included in the basic distribution. |
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Reading matrices from a MATLAB file |
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----------------------------------- |
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The `MatlabReader` class provides static functions to list all matrices stored in a MAT file or stream, |
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and to read them individually as Math.NET matrices: |
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[lang=csharp] |
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using MathNet.Numerics.LinearAlgebra; |
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using MathNet.Numerics.Data.Matlab; |
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// read the first matrix as double |
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Matrix<double> m = MatlabReader.Read<double>("collection.mat"); |
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// read a specific matrix named "vd": |
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Matrix<double> m = MatlabReader.Read<double>("collection.mat", "vd"); |
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// we can also choose to convert to a different type: |
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Matrix<Complex> m = MatlabReader.Read<Complex>("collection.mat"); |
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// read all matrices of a file by name into a dictionary |
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Dictionary<string,Matrix<double>> ms = |
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MatlabReader.ReadAll<double>("collection.mat"); |
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// read the matrices named "Ad" and "vd" into a dictionary |
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var ms = MatlabReader.ReadAll<double>("collection.mat", "vd", "Ad"); |
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Alternatively the reader can list all matrices of a file into named data elements, |
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which can then be read into matrices individually. This is useful e.g. if we need to |
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read some of the matrices to a different type: |
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[lang=csharp] |
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List<MatlabMatrix> ms = MatlabReader.List("collection.mat"); |
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Matrix<double> Ad = MatlabReader.Unpack<double>(ms.Find(m => m.Name == "Ad")); |
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Matrix<float> vd = MatlabReader.Unpack<float>(ms.Find(m => m.Name == "vd")); |
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Writing matrices to a MATLAB file |
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--------------------------------- |
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The dual to the reader above is the `MatlabWriter` class that can serialize matrices |
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to a MATLAB file or stream. Like the reader, the writer can use `MatlabMatrix` data elements |
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to compose packed matrices into a file. Each matrix has a name which must not contain spaces. |
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[lang=csharp] |
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var matrices = new List<MatlabMatrix>(); |
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m.Add(MatlabWriter.Pack(myFirstMatrix, "m1"); |
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m.Add(MatlabWriter.Pack(mySecondMatrix, "m2"); |
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MatlabWrier.Store("file.mat", matrices); |
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But there are also direct routines if only a single matrix or matrices of all the same data type |
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are to be stored in a file: |
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[lang=csharp] |
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// write a single matrix "myMatrix" and name it "m1". |
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MatlabWriter.Write("file.mat", myMatrix, "m1"); |
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// write multiple matrices, from a list of matrices and a list of their names: |
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MatlabWriter.Write("file.mat", new[] { m1, m2 }, new[] { "m1", "m2" }); |
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// write a dictionary of matrices: |
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var dict = new Dictionary<string, Matrix<double>>(); |
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dict.Add("m1", m1); |
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dict.Add("m2", m2); |
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MatlabWriter.Write("file.mat", dict); |
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Alternatives |
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------------ |
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The data extension packages also offer other ways to serialize a matrix to a text file. |
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Among others: |
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* [Delimited Text Files (CSV & TSV)](CSV.html) |
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* [NIST MatrixMarket text files](MatrixMarket.html) |
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*) |
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@ -0,0 +1,62 @@ |
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(*** hide ***) |
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#I "../../out/lib/net40" |
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#r "MathNet.Numerics.dll" |
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#r "MathNet.Numerics.FSharp.dll" |
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(** |
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NIST MatrixMarket Text Files |
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============================ |
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MatrixMarket is both a [vast repository of test data](http://math.nist.gov/MatrixMarket/) |
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and a text-based [exchange file format](http://math.nist.gov/MatrixMarket/formats.html) provided by NIST. |
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Being text-based makes it convenient to deal with and program against, and also works well with versioning |
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tools like [Git](http://www.git-scm.com/). But other than [CSV](CSV.html) it can also store sparse matrices in a compact way. |
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Math.NET Numerics provides basic support for MatrixMarket files with the **MathNet.Numerics.Data.Text** package, |
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which is available on NuGet as separate package and not included in the basic distribution. |
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Reading a matrix from a MatrixMarket file |
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----------------------------------------- |
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The `MatrixMarketReader` class provides static functions to read a matrix or a vector from a file or string. |
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It can read from: |
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* **TextReader**: If you have your delimited data already in memory in a string, |
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you can use this method using a StringReader. |
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* **Stream**: read directly from a stream, e.g. a MemoryStream, FileStream or NetworkStream. |
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* **File Path (string)**: read from a file, specified by the file system path. Optionally GZip compressed. |
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All these functions expect the data type of the matrix to be generated as generic type argument. |
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Only Double, Single, Complex and Complex32 are supported. |
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Example: |
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[lang=csharp] |
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using MathNet.Numerics.Data.Text; |
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Matrix<double> matrix = MatrixMarketReader.ReadMatrix<double>("fidap007.mtx"); |
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Writing a matrix to a MatrixMarket file |
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--------------------------------------- |
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The dual to the reader above is the `MatrixMarketWriter` class that can serialize a matrix or vector |
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to a MatrixMarket text file, stream or TextWriter. |
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Example: |
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[lang=csharp] |
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MatrixMarketWriter.WriteMatrix("matrix.mtx", m); |
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Alternatives |
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------------ |
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The data extension packages also offer other ways to serialize a matrix to a binary stream or file. |
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Among others: |
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* [Delimited Text Files (CSV & TSV)](CSV.html) |
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* [MATLAB Level-5 Mat files](MatlabFiles.html) |
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*) |
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