com.aliasi.matrix

## Class DenseMatrix

• All Implemented Interfaces:
Matrix

```public class DenseMatrix
extends AbstractMatrix```
A `DenseMatrix` is a matrix implementation suitable for matrices with primarily non-zero values. The dimensionality of a dense matrix is set at construction time and immutable afterwards. Values may be specified at construction time or given default values; they are mutable and may be reset after construction.

Implementation Note: A dense matrix represents the values with a two-dimensional array of primitive double values.

Since:
LingPipe2.0
Version:
2.4
Author:
Bob Carpenter
• ### Constructor Summary

Constructors
Constructor and Description
`DenseMatrix(double[][] values)`
Construct a dense matrix with the specified values.
```DenseMatrix(int numRows, int numColumns)```
Construct a dense matrix with the specified positive number of rows and columns.
• ### Method Summary

All Methods
Modifier and Type Method and Description
`int` `numColumns()`
Returns the number of columns in the matrix.
`int` `numRows()`
Returns the number of rows in the matrix.
`void` ```setValue(int row, int column, double value)```
Throw an unsupported operation exception.
`double` ```value(int row, int column)```
Returns the value in the matrix at the specified row and column.
• ### Methods inherited from class com.aliasi.matrix.AbstractMatrix

`columnVector, equals, hashCode, rowVector`
• ### Methods inherited from class java.lang.Object

`clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`
• ### Constructor Detail

• #### DenseMatrix

```public DenseMatrix(int numRows,
int numColumns)```
Construct a dense matrix with the specified positive number of rows and columns. All values are initially `0.0`.
Parameters:
`numRows` - Number of rows for this matrix.
`numColumns` - Number of columns for this matrix.
Throws:
`IllegalArgumentException` - If either the number of rows or columns is not positive.
• #### DenseMatrix

`public DenseMatrix(double[][] values)`
Construct a dense matrix with the specified values. Row dimensionality is determined by the dimensionality of the specified array of values. Column dimensionality is specified as the maximum length of a row of specified values. Shorter rows in the specified values are filled with `0.0`. All labels are initialized to `null`.
Parameters:
`values` - Two-dimensional array of values on which to base this matrix.
Throws:
`IllegalArgumentException` - If the either dimension of the values array is 0.
• ### Method Detail

• #### numRows

`public final int numRows()`
Description copied from interface: `Matrix`
Returns the number of rows in the matrix.
Specified by:
`numRows` in interface `Matrix`
Specified by:
`numRows` in class `AbstractMatrix`
Returns:
The number of rows in the matrix.
• #### numColumns

`public final int numColumns()`
Description copied from interface: `Matrix`
Returns the number of columns in the matrix.
Specified by:
`numColumns` in interface `Matrix`
Specified by:
`numColumns` in class `AbstractMatrix`
Returns:
The number of columns in the matrix.
• #### value

```public double value(int row,
int column)```
Description copied from interface: `Matrix`
Returns the value in the matrix at the specified row and column.
Specified by:
`value` in interface `Matrix`
Specified by:
`value` in class `AbstractMatrix`
Parameters:
`row` - The specified row.
`column` - The specified column.
Returns:
The value in the matrix at the specified row and column.
• #### setValue

```public void setValue(int row,
int column,
double value)```
Description copied from class: `AbstractMatrix`
Throw an unsupported operation exception. This method should be overriden by value mutable subclasses.
Specified by:
`setValue` in interface `Matrix`
Overrides:
`setValue` in class `AbstractMatrix`
Parameters:
`row` - Ignored.
`column` - Ignored.
`value` - Ignored.