## org.biojava.bio.alignment
Class NeedlemanWunsch

    java.lang.Object
      org.biojava.bio.alignment.SequenceAlignment
          org.biojava.bio.alignment.NeedlemanWunsch

Direct Known Subclasses:
  SmithWaterman

    public class NeedlemanWunsch

extends SequenceAlignment

Needleman and Wunsch defined the problem of global sequence alignments, from the first till the last symbol of a sequence. This class is able to perform such global sequence comparisons efficiently by dynamic programming. If inserts and deletes are equally expensive and as expensive as the extension of a gap, the alignment method of this class does not use affine gap penalties. Otherwise it does. Those costs need four times as much memory, which has significant effects on the run time, if the computer needs to swap.

Since:
  1.5
Author:
  Andreas Dräger, Gero Greiner, Mark Schreiber

Field Summary
`protected String` `alignment` The result of a successful alignment as a simple String.
`protected int[][]` `CostMatrix` A matrix with the size length(sequence1) times length(sequence2)
`protected Alignment` `pairalign` The result of a successful alignment
`protected SubstitutionMatrix` `subMatrix` A matrix with the size length(alphabet) times length(alphabet)

Constructor Summary
`NeedlemanWunsch(short match, short replace, short insert, short delete, short gapExtend, SubstitutionMatrix subMat)` Constructs a new Object with the given parameters based on the Needleman-Wunsch algorithm The alphabet of sequences to be aligned will be taken from the given substitution matrix.

Method Summary
`List<Alignment>` `alignAll(SequenceIterator source, SequenceDB subjectDB)`
`Alignment` `getAlignment(SymbolList query, SymbolList target)` This method is good if one wants to reuse the alignment calculated by this class in another BioJava class.
`String` `getAlignmentString()`
`short` `getDelete()` Returns the current expenses of a single delete operation.
`int` `getEditDistance()` This gives the edit distance according to the given parameters of this certain object.
`short` `getGapExt()` Returns the current expenses of any extension of a gap operation.
`short` `getInsert()` Returns the current expenses of a single insert operation.
`short` `getMatch()` Returns the current expenses of a single match operation.
`short` `getReplace()` Returns the current expenses of a single replace operation.
`protected static int` `min(int x, int y, int z)` This just computes the minimum of three integer values.
`int` `pairwiseAlignment(SymbolList query, SymbolList subject)` Global pairwise sequence alignment of two BioJava-Sequence objects according to the Needleman-Wunsch-algorithm.
`static void` `printAlignment(String align)` prints the alignment String on the screen (standard output).
`static String` `printCostMatrix(int[][] CostMatrix, char[] queryChar, char[] targetChar)` Prints a String representation of the CostMatrix for the given Alignment on the screen.
`void` `setDelete(short del)` Sets the penalty for a delete operation to the specified value.
`void` `setGapExt(short ge)` Sets the penalty for an extension of any gap (insert or delete) to the specified value.
`void` `setInsert(short ins)` Sets the penalty for an insert operation to the specified value.
`void` `setMatch(short ma)` Sets the penalty for a match operation to the specified value.
`void` `setReplace(short rep)` Sets the penalty for a replace operation to the specified value.
`void` `setSubstitutionMatrix(SubstitutionMatrix matrix)` Sets the substitution matrix to be used to the specified one.

Methods inherited from class org.biojava.bio.alignment.SequenceAlignment
`formatOutput`

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

Field Detail

### CostMatrix

    protected int[][] CostMatrix

  A matrix with the size length(sequence1) times length(sequence2)

### subMatrix

    protected SubstitutionMatrix subMatrix

  A matrix with the size length(alphabet) times length(alphabet)

### pairalign

    protected Alignment pairalign

  The result of a successful alignment

### alignment

    protected String alignment

  The result of a successful alignment as a simple String.

Constructor Detail

### NeedlemanWunsch

    public NeedlemanWunsch(short match,
                           short replace,
                           short insert,
                           short delete,
                           short gapExtend,
                           SubstitutionMatrix subMat)

  Constructs a new Object with the given parameters based on the Needleman-Wunsch algorithm The alphabet of sequences to be aligned will be taken from the given substitution matrix.

  Parameters:
    `match` - This gives the costs for a match operation. It is only used, if there is no entry for a certain match of two symbols in the substitution matrix (default value).
    `replace` - This is like the match parameter just the default, if there is no entry in the substitution matrix object.
    `insert` - The costs of a single insert operation.
    `delete` - The expenses of a single delete operation.
    `gapExtend` - The expenses of an extension of a existing gap (that is a previous insert or delete. If the costs for insert and delete are equal and also equal to gapExtend, no affine gap penalties will be used, which saves a significant amount of memory.
    `subMat` - The substitution matrix object which gives the costs for matches and replaces.

Method Detail

### setSubstitutionMatrix

    public void setSubstitutionMatrix(SubstitutionMatrix matrix)

  Sets the substitution matrix to be used to the specified one. Afterwards it is only possible to align sequences of the alphabet of this substitution matrix.

  Parameters:
    `matrix` - an instance of a substitution matrix.

### setInsert

    public void setInsert(short ins)

  Sets the penalty for an insert operation to the specified value.

  Parameters:
    `ins` - costs for a single insert operation

### setDelete

    public void setDelete(short del)

  Sets the penalty for a delete operation to the specified value.

  Parameters:
    `del` - costs for a single deletion operation

### setGapExt

    public void setGapExt(short ge)

  Sets the penalty for an extension of any gap (insert or delete) to the specified value.

  Parameters:
    `ge` - costs for any gap extension

### setMatch

    public void setMatch(short ma)

  Sets the penalty for a match operation to the specified value.

  Parameters:
    `ma` - costs for a single match operation

### setReplace

    public void setReplace(short rep)

  Sets the penalty for a replace operation to the specified value.

  Parameters:
    `rep` - costs for a single replace operation

### getInsert

    public short getInsert()

  Returns the current expenses of a single insert operation.

  Returns:
    insert

### getDelete

    public short getDelete()

  Returns the current expenses of a single delete operation.

  Returns:
    delete

### getGapExt

    public short getGapExt()

  Returns the current expenses of any extension of a gap operation.

  Returns:
    gapExt

### getMatch

    public short getMatch()

  Returns the current expenses of a single match operation.

  Returns:
    match

### getReplace

    public short getReplace()

  Returns the current expenses of a single replace operation.

  Returns:
    replace

### printCostMatrix

    public static String printCostMatrix(int[][] CostMatrix,
                                         char[] queryChar,
                                         char[] targetChar)

  Prints a String representation of the CostMatrix for the given Alignment on the screen. This can be used to get a better understanding of the algorithm. There is no other purpose. This method also works for all extensions of this class with all kinds of matrices.

  Parameters:
    `CostMatrix` - The matrix that contains all expenses for swapping symbols.
    `queryChar` - a character representation of the query sequence (`mySequence.seqString().toCharArray()`).
    `targetChar` - a character representation of the target sequence.
  Returns:
    a String representation of the matrix.

### printAlignment

    public static void printAlignment(String align)

  prints the alignment String on the screen (standard output).

  Parameters:
    `align` - The parameter is typically given by the `getAlignmentString()` method.

### getAlignment

    public Alignment getAlignment(SymbolList query,
                                  SymbolList target)
                           throws Exception

  This method is good if one wants to reuse the alignment calculated by this class in another BioJava class. It just performs `pairwiseAlignment` and returns an `Alignment` instance containing the two aligned sequences.

  Specified by:
    `getAlignment` in class `SequenceAlignment`
  Returns:
    Alignment object containing the two gapped sequences constructed from query and target.
  Throws:
    `Exception`

### getEditDistance

    public int getEditDistance()

  This gives the edit distance according to the given parameters of this certain object. It returns just the last element of the internal cost matrix (left side down). So if you extend this class, you can just do the following: `int myDistanceValue = foo; this.CostMatrix = new int[1][1]; this.CostMatrix[0][0] = myDistanceValue;`

  Returns:
    returns the edit_distance computed with the given parameters.

### min

    protected static int min(int x,
                             int y,
                             int z)

  This just computes the minimum of three integer values.

  Parameters:
    `x` -
    `y` -
    `z` -
  Returns:
    Gives the minimum of three integers

### getAlignmentString

    public String getAlignmentString()
                              throws BioException

  Specified by:
    `getAlignmentString` in class `SequenceAlignment`
  Returns:
    a string representation of the alignment
  Throws:
    `BioException`

### alignAll

    public List<Alignment> alignAll(SequenceIterator source,
                                    SequenceDB subjectDB)
                             throws NoSuchElementException,
                                    BioException

  Specified by:
    `alignAll` in class `SequenceAlignment`
  Parameters:
    `source` - a SequenceIterator containing a set of sequences to be aligned with
    `subjectDB` - the SequenceDB containing another set of sequences.
  Returns:
    a list containing the results of all single alignments performed by this method.
  Throws:
    `NoSuchElementException`
    `BioException`

### pairwiseAlignment

    public int pairwiseAlignment(SymbolList query,
                                 SymbolList subject)
                          throws BioRuntimeException

  Global pairwise sequence alignment of two BioJava-Sequence objects according to the Needleman-Wunsch-algorithm.

  Specified by:
    `pairwiseAlignment` in class `SequenceAlignment`
  Returns:
    score of the alignment or the distance.
  Throws:
    `BioRuntimeException`
  See Also:
    `SequenceAlignment.pairwiseAlignment(org.biojava.bio.symbol.SymbolList, org.biojava.bio.symbol.SymbolList)`