# Module: matrix

A utility module that contains some common matrix operations as well as decompositions
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### Methods

#### (static) getMatrix(number[][]opt, arrayopt, numberopt, numberopt)

Get a submatrix of matrix
##### Parameters:
Name Type Attributes Description
`number[][]` <optional>
matrix - original matrix
`array` <optional>
r - Array of row indices.
`number` <optional>
j0 - Initial column index
`number` <optional>
j1 - Final column index
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##### Returns:
[number[][]] X is the submatrix matrix(r(:),j0:j1)

#### (static) getSubMatrix(number[][]opt, numberopt, numberopt, numberopt, numberopt)

Get a submatrix of matrix
##### Parameters:
Name Type Attributes Description
`number[][]` <optional>
matrix - original matrix
`number` <optional>
i0 - Initial row index
`number` <optional>
i1 - Final row index
`number` <optional>
j0 - Initial column index
`number` <optional>
j1 - Final column index
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##### Returns:
matrix(i0:i1,j0:j1)

#### (static) LUDecomposition() → {Array.<Array.<number>>}

LUDecomposition to solve A*X = B, based on WEKA code
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##### Returns:
X so that L*U*X = B(piv,:)
Type
Array.<Array.<number>>

#### (static) mult(matrix1, matrix2) → {Array.<Array.<number>>}

Linear algebraic matrix multiplication, matrix1 * matrix2
##### Parameters:
Name Type Description
`matrix1` Array.<Array.<number>>
`matrix2` Array.<Array.<number>>
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##### Returns:
Matrix product, matrix1 * matrix2
Type
Array.<Array.<number>>

#### (static) QRDecomposition(number[][]opt, number[][]opt)

Least squares solution of A*X = B, based on WEKA code
##### Parameters:
Name Type Attributes Description
`number[][]` <optional>
A - left side matrix to be solved
`number[][]` <optional>
B - a matrix with as many rows as A and any number of columns.
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##### Returns:
[number[][]] X - that minimizes the two norms of QR*X-B.

#### (static) transpose(matrix) → {Array.<Array.<number>>}

Transposes an mxnnumber[][]
##### Parameters:
Name Type Description
`matrix` Array.<Array.<number>> of mxn dimensionality
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##### Returns:
transposed matrix
Type
Array.<Array.<number>>