com.numericalmethod.suanshu.matrix.doubles.operation

Class CreateMatrix

java.lang.Object

com.numericalmethod.suanshu.matrix.doubles.operation.CreateMatrix

public class CreateMatrix
extends java.lang.Object

These are the utility functions to create a new matrix/vector from existing ones.

Method Summary

Modifier and Type	Method and Description
static DenseMatrix	cbind(java.util.List<Vector> vectors) Combine a list of vectors by columns.
static DenseMatrix	cbind(Matrix... matrices) Combine an array of matrices by columns.
static DenseMatrix	cbind(Vector... vectors) Combine an array of vectors by columns.
static DenseMatrix	columns(Matrix A, int[] cols) Construct a sub-matrix from the columns of a matrix.
static DenseMatrix	columns(Matrix A, int begin, int end) Construct a sub-matrix from the columns of a matrix.
static Matrix	copyAndReplace(Matrix original, int rowFrom, int rowTo, int colFrom, int colTo, Matrix replacement) Deprecated. Not supported yet.
static DiagonalMatrix	diagonalMatrix(Matrix A) Get the diagonal of a matrix.
static DenseMatrix	rbind(java.util.List<Vector> vectors) Combine a list of array of vectors by rows.
static DenseMatrix	rbind(Matrix... matrices) Combine an array of matrices by rows.
static DenseMatrix	rbind(Vector... vectors) Combine an array of vectors by rows.
static Matrix	replace(Matrix original, int rowFrom, int rowTo, int colFrom, int colTo, Matrix replacement) Replace a sub-matrix of a matrix with a smaller matrix.
static DenseMatrix	rows(Matrix A, int[] rows) Construct a sub-matrix from the rows of a matrix.
static DenseMatrix	rows(Matrix A, int begin, int end) Construct a sub-matrix from the rows of a matrix.
static DenseMatrix	subMatrix(Matrix A, int[] rows, int[] cols) Construct a sub-matrix from the intersections of rows and columns of a matrix.
static DenseMatrix	subMatrix(Matrix A, int rowFrom, int rowTo, int colFrom, int colTo) Construct a sub-matrix from the four corners of a matrix.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

cbind

public static DenseMatrix cbind(Vector... vectors)

Combine an array of vectors by columns. The vectors must have the same length.

Parameters:

vectors - an array of vectors, e.g., v₁, v₂, v₃, ...

Returns:

[v₁ v₂ v₃ ...]

cbind

public static DenseMatrix cbind(java.util.List<Vector> vectors)

Combine a list of vectors by columns. The vectors must have the same length.

Parameters:

vectors - a list of vectors, e.g., v₁, v₂, v₃, ...

Returns:

[v₁ v₂ v₃ ...]

cbind

public static DenseMatrix cbind(Matrix... matrices)

Combine an array of matrices by columns. The matrices must have the same number of rows.

Parameters:

matrices - an array of matrices, e.g., A₁, A₂, A₃, ...

Returns:

[A₁ A₂ A₃ ...]

rbind

public static DenseMatrix rbind(Vector... vectors)

Combine an array of vectors by rows. The vectors must have the same length.

Parameters:

vectors - an array of vector, e.g., v₁, v₂, v₃, ...

Returns:

\[ \begin{bmatrix} v_1\\ v_2\\ v_3\\ ... \end{bmatrix} \]

Throws:

java.lang.IllegalArgumentException - if the vectors form a jagged array

rbind

public static DenseMatrix rbind(java.util.List<Vector> vectors)

Combine a list of array of vectors by rows. The vectors must have the same length.

Parameters:

vectors - a list of vector, e.g., v₁, v₂, v₃, ...

Returns:

\[ \begin{bmatrix} v_1\\ v_2\\ v_3\\ ... \end{bmatrix} \]

Throws:

java.lang.IllegalArgumentException - if the vectors form a jagged array

rbind

public static DenseMatrix rbind(Matrix... matrices)

Combine an array of matrices by rows. The matrices must have the same number of columns.

Parameters:

matrices - an array of matrices, e.g., A₁, A₂, A₃, ...

Returns:

\[ \begin{bmatrix} A_1\\ A_2\\ A_3\\ ... \end{bmatrix} \]

subMatrix

public static DenseMatrix subMatrix(Matrix A,
                                    int rowFrom,
                                    int rowTo,
                                    int colFrom,
                                    int colTo)

Construct a sub-matrix from the four corners of a matrix.

Parameters:

A - a matrix

rowFrom - the beginning row index

rowTo - the ending row index

colFrom - the beginning column index

colTo - the ending column index

Returns:

A[rowFrom:rowTo, colFrom:colTo]

subMatrix

public static DenseMatrix subMatrix(Matrix A,
                                    int[] rows,
                                    int[] cols)

Construct a sub-matrix from the intersections of rows and columns of a matrix.

Parameters:

A - a matrix

rows - the rows to be extracted

cols - the columns to be extracted

Returns:

A[rows, cols]

rows

public static DenseMatrix rows(Matrix A,
                               int[] rows)

Construct a sub-matrix from the rows of a matrix.

Parameters:

A - a matrix

rows - the rows to be extracted

Returns:

A[rows, *]

rows

public static DenseMatrix rows(Matrix A,
                               int begin,
                               int end)

Construct a sub-matrix from the rows of a matrix.

Parameters:

A - a matrix

begin - the beginning row index (counting from 1)

end - the ending row index (counting from 1)

Returns:

A[begin:end, *]

columns

public static DenseMatrix columns(Matrix A,
                                  int[] cols)

Construct a sub-matrix from the columns of a matrix.

Parameters:

A - a matrix

cols - the columns to be extracted

Returns:

A[*, cols]

columns

public static DenseMatrix columns(Matrix A,
                                  int begin,
                                  int end)

Construct a sub-matrix from the columns of a matrix.

Parameters:

A - a matrix

begin - the beginning column index (counting from 1)

end - the ending column index (counting from 1)

Returns:

A[*, begin:end]

replace

public static Matrix replace(Matrix original,
                             int rowFrom,
                             int rowTo,
                             int colFrom,
                             int colTo,
                             Matrix replacement)

Replace a sub-matrix of a matrix with a smaller matrix. This method is best NOT to apply to SymmetricMatrix because this method does not ensure the symmetry property after replacement.

Note that The original matrix is modified afterward (for performance reason in case of a big matrix). No new Matrix instance is constructed.

Parameters:

original - the matrix whose entries are to be replaced

rowFrom - the beginning row index

rowTo - the ending row index

colFrom - the beginning column index

colTo - the ending column index

replacement - the matrix to be inserted into the original matrix

Returns:

the modified matrix

copyAndReplace

@Deprecated
public static Matrix copyAndReplace(Matrix original,
                                                int rowFrom,
                                                int rowTo,
                                                int colFrom,
                                                int colTo,
                                                Matrix replacement)

Deprecated. Not supported yet.

Make a copy of a matrix and then replace a sub-matrix of the copy. The two input matrices are not modified. This method is best NOT to apply to SymmetricMatrix because this method does not ensure the symmetry property after replacement.

Parameters:

original - the matrix whose entries are to be replaced

rowFrom - the beginning row index

rowTo - the ending row index

colFrom - the beginning column index

colTo - the ending column index

replacement - the matrix to be inserted into the original matrix

Returns:

the modified matrix

diagonalMatrix

public static DiagonalMatrix diagonalMatrix(Matrix A)

Get the diagonal of a matrix.

Parameters:

A - a matrix

Returns:

a diagonal matrix whose diagonal entries are A_i,i, zeros elsewhere

Throws:

java.lang.IllegalArgumentException - if A is not square