## org.biojava.bio.alignment
Class SubstitutionMatrix

    java.lang.Object
      org.biojava.bio.alignment.SubstitutionMatrix

    public class SubstitutionMatrix

extends Object

This object is able to read a substitution matrix file and constructs a short matrix in memory. Every single element of the matrix can be accessed by the method `getValueAt` with the parameters being two BioJava symbols. This is why it is not necessary to access the matrix directly. If there is no value for the two specified `Symbol`s an `Exception` is thrown.

Substitution matrix files, are available at the NCBI FTP directory.

Author:
  Andreas Dräger <andreas.draeger@uni-tuebingen.de>

Field Summary
`protected FiniteAlphabet` `alphabet`
`protected Map<Symbol,Integer>` `colSymbols`
`protected String` `description`
`protected short[][]` `matrix`
`protected short` `max`
`protected short` `min`
`protected String` `name`
`protected Map<Symbol,Integer>` `rowSymbols`

Constructor Summary
`SubstitutionMatrix(File file)` This constructor can be used to guess the alphabet of this substitution matrix.
`SubstitutionMatrix(FiniteAlphabet alpha, File matrixFile)` This constructs a `SubstitutionMatrix` object that contains two `Map` data structures having BioJava symbols as keys and the value being the index of the matrix containing the substitution score.
`SubstitutionMatrix(FiniteAlphabet alpha, short match, short replace)` Constructs a SubstitutionMatrix with every Match and every Replace having the same expenses given by the parameters.
`SubstitutionMatrix(FiniteAlphabet alpha, String matrixString, String name)` With this constructor it is possible to construct a SubstitutionMatrix object from a substitution matrix file.

Method Summary
`FiniteAlphabet` `getAlphabet()` Gives the alphabet used by this matrix.
`String` `getDescription()` This gives you the description of this matrix if there is one.
`short` `getMax()` The maximum score in this matrix.
`short` `getMin()` The minimum score of this matrix.
`String` `getName()` Every substitution matrix has a name like "BLOSUM30" or "PAM160".
`static SubstitutionMatrix` `getSubstitutionMatrix(BufferedReader reader)` This constructor can be used to guess the alphabet of this substitution matrix.
`short` `getValueAt(Symbol row, Symbol col)` There are some substitution matrices containing more columns than lines.
`SubstitutionMatrix` `normalizeMatrix()` With this method you can get a “normalized” `SubstitutionMatrix` object; however, since this implementation uses an short matrix, the normalized matrix will be scaled by ten.
`void` `printMatrix()` Just to perform some test.
`void` `setDescription(String desc)` Sets the description to the given value.
`String` `stringnifyDescription()` Converts the description of the matrix to a String.
`String` `stringnifyMatrix()` Creates a `String` representation of this matrix.
`String` `toString()` Overrides the inherited method.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Field Detail

### rowSymbols

    protected Map<Symbol,Integer> rowSymbols

### colSymbols

    protected Map<Symbol,Integer> colSymbols

### matrix

    protected short[][] matrix

### min

    protected short min

### max

    protected short max

### alphabet

    protected FiniteAlphabet alphabet

### description

    protected String description

### name

    protected String name

Constructor Detail

### SubstitutionMatrix

    public SubstitutionMatrix(FiniteAlphabet alpha,
                              File matrixFile)
                       throws BioException,
                              NumberFormatException,
                              IOException

  This constructs a `SubstitutionMatrix` object that contains two `Map` data structures having BioJava symbols as keys and the value being the index of the matrix containing the substitution score.

  Parameters:
    `alpha` - the alphabet of the matrix (e.g., DNA, RNA or PROTEIN, or PROTEIN-TERM)
    `matrixFile` - the file containing the substitution matrix. Lines starting with '`#`' are comments. The line starting with a white space, is the table head. Every line has to start with the one letter representation of the Symbol and then the values for the exchange.
  Throws:
    `IOException`
    `BioException`
    `NumberFormatException`

### SubstitutionMatrix

    public SubstitutionMatrix(FiniteAlphabet alpha,
                              String matrixString,
                              String name)
                       throws BioException,
                              NumberFormatException,
                              IOException

  With this constructor it is possible to construct a SubstitutionMatrix object from a substitution matrix file. The given String contains a number of lines separated by `System.getProperty("line.separator")`. Everything else is the same than for the constructor above.

  Parameters:
    `alpha` - The `FiniteAlphabet` to use
    `matrixString` -
    `name` - of the matrix.
  Throws:
    `BioException`
    `IOException`
    `NumberFormatException`

### SubstitutionMatrix

    public SubstitutionMatrix(FiniteAlphabet alpha,
                              short match,
                              short replace)

  Constructs a SubstitutionMatrix with every Match and every Replace having the same expenses given by the parameters. Ambiguous symbols are not considered because there might be to many of them (for proteins).

  Parameters:
    `alpha` -
    `match` -
    `replace` -

### SubstitutionMatrix

    public SubstitutionMatrix(File file)
                       throws NumberFormatException,
                              NoSuchElementException,
                              BioException,
                              IOException

  This constructor can be used to guess the alphabet of this substitution matrix. However, it is recommended to apply another constructor if the alphabet is known.

  Parameters:
    `file` - A file containing a substitution matrix.
  Throws:
    `NumberFormatException`
    `NoSuchElementException`
    `BioException`
    `IOException`

Method Detail

### getSubstitutionMatrix

    public static SubstitutionMatrix getSubstitutionMatrix(BufferedReader reader)
                                                    throws NumberFormatException,
                                                           BioException,
                                                           IOException

  This constructor can be used to guess the alphabet of this substitution matrix. However, it is recommended to apply another constructor if the alphabet is known.

  Parameters:
    `reader` -
  Throws:
    `NumberFormatException`
    `BioException`
    `IOException`

### getValueAt

    public short getValueAt(Symbol row,
                            Symbol col)
                     throws BioException

  There are some substitution matrices containing more columns than lines. This has to do with the ambiguous symbols. Lines are always good, columns might not contain the whole information. The matrix is supposed to be symmetric anyway, so you can always set the ambiguous symbol to be the first argument.

  Parameters:
    `row` - Symbol of the line
    `col` - Symbol of the column
  Returns:
    expenses for the exchange of symbol row and symbol column.
  Throws:
    `BioException`

### getDescription

    public String getDescription()

  This gives you the description of this matrix if there is one. Normally substitution matrix files like BLOSUM contain some lines of description.

  Returns:
    the comment of the matrix

### getName

    public String getName()

  Every substitution matrix has a name like "BLOSUM30" or "PAM160". This will be returned by this method.

  Returns:
    the name of the matrix.

### getMin

    public short getMin()

  The minimum score of this matrix.

  Returns:
    minimum of the matrix.

### getMax

    public short getMax()

  The maximum score in this matrix.

  Returns:
    maximum of the matrix.

### setDescription

    public void setDescription(String desc)

  Sets the description to the given value.

  Parameters:
    `desc` - a description. This doesn't have to start with '#'.

### getAlphabet

    public FiniteAlphabet getAlphabet()

  Gives the alphabet used by this matrix.

  Returns:
    the alphabet of this matrix.

### stringnifyMatrix

    public String stringnifyMatrix()

  Creates a `String` representation of this matrix.

  Returns:
    a string representation of this matrix without the description.

### stringnifyDescription

    public String stringnifyDescription()

  Converts the description of the matrix to a String.

  Returns:
    Gives a description with approximately 60 letters on every line separated by `System.getProperty("line.separator")`. Every line starts with `#`.

### toString

    public String toString()

  Overrides the inherited method.

  Overrides:
    `toString` in class `Object`
  Returns:
    Gives a string representation of the SubstitutionMatrix. This is a valid input for the constructor which needs a matrix string. This String also contains the description of the matrix if there is one.

### printMatrix

    public void printMatrix()

  Just to perform some test. It prints the matrix on the screen.

### normalizeMatrix

    public SubstitutionMatrix normalizeMatrix()
                                       throws BioException,
                                              NumberFormatException,
                                              IOException

  With this method you can get a “normalized” `SubstitutionMatrix` object; however, since this implementation uses an short matrix, the normalized matrix will be scaled by ten. If you need values between zero and one, you have to divide every value returned by `getValueAt` by ten.

  Returns:
    a new and normalized `SubstitutionMatrix` object given by this substitution matrix. Because this uses an `short` matrix, all values are scaled by 10.
  Throws:
    `BioException`
    `IOException`
    `NumberFormatException`