LinearAlgebra

Data Structures
struct	Matrix
	Represents a matrix of double-precision data. More...

Functions
Matrix	slap_NewMatrix (int rows, int cols)
	Allocate a new matrix on the heap. More...
Matrix	slap_NewMatrixZeros (int rows, int cols)
	Allocate a new matrix on the heap, initialized with zeros. More...
int	slap_MatrixSetConst (Matrix *mat, double val)
	Sets all of the elements in a matrix to a single value. More...
int	slap_FreeMatrix (Matrix *mat)
	Free the data for a matrix. More...
int	slap_MatrixNumElements (const Matrix *mat)
	Get the number of elements in a matrix, i.e. m * n. More...
int	slap_MatrixGetLinearIndex (const Matrix *mat, int row, int col)
	Get the linear index for a given row and column in the matrix. More...
double *	slap_MatrixGetElementTranspose (const Matrix *mat, int row, int col, bool istranposed)
	Get the element of a matrix or its transpose. More...
int	slap_MatrixSetElement (Matrix *mat, int row, int col, double val)
	The a matrix element to a given value. More...
double *	slap_MatrixGetElement (const Matrix *mat, int row, int col)
	Get the element of a matrix given row, column indices. More...
int	slap_MatrixCopyTranspose (Matrix *dest, Matrix *src)
	Copy a matrix to another matrix, transposed. More...
int	slap_MatrixCopy (Matrix *dest, Matrix *src)
	Copy a matrix to another matrix. More...
int	slap_MatrixCopyFromArray (Matrix *mat, const double *data)
	Copy the data from an array into the matrix, columnwise. More...
int	slap_MatrixScaleByConst (Matrix *mat, double alpha)
	Scale a matrix by a constant factor. More...
double	slap_MatrixNormedDifference (Matrix *A, Matrix *B)
	Return the normed difference between 2 matrices of the same size. More...
int	slap_MatrixFlatten (Matrix *mat)
	Flatten a 2D matrix to a column vector. More...
int	slap_MatrixFlattenToRow (Matrix *mat)
	Flatten a 2D matrix to a row vector. More...
int	slap_PrintMatrix (const Matrix *mat)
	Print the elements of a matrix to stdout. More...
int	slap_PrintRowVector (const Matrix *mat)
	Print the entire matrix as a row vector. More...
int	slap_SetMatrixSize (Matrix *mat, int rows, int cols)
	Set the dimensions of the matrix. More...

Detailed Description

Function Documentation

slap_FreeMatrix()

int slap_FreeMatrix

(

Matrix *

mat

)

Free the data for a matrix.

Note this does NOT attempt to free the matrix object itself, only the data it wraps.

Parameters

mat

Postcondition

mat.data will be NULL.

Returns

0 if successful

slap_MatrixCopy()

int slap_MatrixCopy	(	Matrix *	dest,
		Matrix *	src
	)

Copy a matrix to another matrix.

Parameters

dest	a matrix of size (m,n)
src	a matrix of size (n,m)

Returns

0 if successful

slap_MatrixCopyFromArray()

int slap_MatrixCopyFromArray	(	Matrix *	mat,
		const double *	data
	)

Copy the data from an array into the matrix, columnwise.

Parameters

mat	Matrix with nonzero size
data	Data to be copied into the array. Must have length of at least mat.rows * mat.cols.

Returns

0 if successful

slap_MatrixCopyTranspose()

int slap_MatrixCopyTranspose	(	Matrix *	dest,
		Matrix *	src
	)

Copy a matrix to another matrix, transposed.

Parameters

dest	a matrix of size (m,n)
src	a matrix of size (n,m)

Returns

0 if successful

slap_MatrixFlatten()

int slap_MatrixFlatten

(

Matrix *

mat

)

Flatten a 2D matrix to a column vector.

Changes the row and column data so that the matrix is now a column vector. The underlying data is unchanged.

Parameters

mat	Matrix to be flattened.

Returns

0 if successful

slap_MatrixFlattenToRow()

int slap_MatrixFlattenToRow

(

Matrix *

mat

)

Flatten a 2D matrix to a row vector.

Changes the row and column data so that the matrix is now a row vector. The underlying data is unchanged.

Parameters

mat	Matrix to be flattened

Returns

0 if successful

slap_MatrixGetElement()

double* slap_MatrixGetElement	(	const Matrix *	mat,
		int	row,
		int	col
	)

Get the element of a matrix given row, column indices.

Parameters

mat	Matrix of nonzero size
row	Row index
col	Column index

Returns

A pointer to the element of the matrix. NULL for invalid input.

slap_MatrixGetElementTranspose()

double* slap_MatrixGetElementTranspose	(	const Matrix *	mat,
		int	row,
		int	col,
		bool	istranposed
	)

Get the element of a matrix or its transpose.

If istransposed is false, then this method acts just like MatrixGetElement(). Otherwise, it is equalivalent to flipping the row and col arguments to MatrixGetElement().

Parameters

mat	Matrix with nonzero size and initialized data
row	Row index
col	Column index
istranposed	Are the indicies for the transpose of A?

Returns

Pointer to the data at the given element.

slap_MatrixGetLinearIndex()

int slap_MatrixGetLinearIndex	(	const Matrix *	mat,
		int	row,
		int	col
	)

Get the linear index for a given row and column in the matrix.

Converts a cartesian index of row and column into a linear index for accessing an element of the underlying data.

Parameters

mat	Matrix with nonzero size and initialized data
row	Row index
col	Column index

Returns

Linear index corresponding to row and col. Returns -1 for a bad input.

slap_MatrixNormedDifference()

double slap_MatrixNormedDifference	(	Matrix *	A,
		Matrix *	B
	)

Return the normed difference between 2 matrices of the same size.

Returns \( \sqrt{\sum_{i=0}^{m-1} \sum_{j=0}^{n-1} (A_{ij} - B_{ij})^2 } \)

Parameters

A	A matrix of dimension (m,n)
B	A matrix of dimension (m,n)

Returns

slap_MatrixNumElements()

int slap_MatrixNumElements

(

const Matrix *

mat

)

Get the number of elements in a matrix, i.e. m * n.

Parameters

mat	Any matrix

Returns

Number of elements in the matrix

slap_MatrixScaleByConst()

int slap_MatrixScaleByConst	(	Matrix *	mat,
		double	alpha
	)

Scale a matrix by a constant factor.

Parameters

mat	Fully initialized matrix of non-zero size. Values will be modified.
alpha	scalar by which to multiply the matrix

Returns

0 if successsful

slap_MatrixSetConst()

int slap_MatrixSetConst	(	Matrix *	mat,
		double	val
	)

Sets all of the elements in a matrix to a single value.

Parameters

mat	Matrix to be modified
val	Value to which each element will be set

Returns

0 if successful

slap_MatrixSetElement()

int slap_MatrixSetElement	(	Matrix *	mat,
		int	row,
		int	col,
		double	val
	)

The a matrix element to a given value.

Parameters

mat	Matrix with nonzero size and initialized data
row	Row index
col	Column index
val	Value to which the element should be set

Returns

0 if successful

slap_NewMatrix()

Matrix slap_NewMatrix	(	int	rows,
		int	cols
	)

Allocate a new matrix on the heap.

Data will not be initialized. Wrapper around a call to malloc. Must be followed by a call to FreeMatrix.

Parameters

rows	number of rows in the matrix
cols	number of columns in the matrix

Returns

A new matrix

slap_NewMatrixZeros()

Matrix slap_NewMatrixZeros	(	int	rows,
		int	cols
	)

Allocate a new matrix on the heap, initialized with zeros.

Data will not be initialized. Wrapper around a call to malloc. Must be followed by a call to FreeMatrix.

Parameters

rows	number of rows in the matrix
cols	number of columns in the matrix

Returns

A new matrix

slap_PrintMatrix()

int slap_PrintMatrix

(

const Matrix *

mat

)

Print the elements of a matrix to stdout.

Precision of the printing can be controlled by the global variable PRECISION.

Parameters

mat	Matrix to be printed

Returns

0 if successful

slap_PrintRowVector()

int slap_PrintRowVector

(

const Matrix *

mat

)

Print the entire matrix as a row vector.

Same result as calling PrintMatrix() after a call to MatrixFlattenToRow().

Parameters

mat	Matrix to be printed

Returns

0 if successful

slap_SetMatrixSize()

int slap_SetMatrixSize	(	Matrix *	mat,
		int	rows,
		int	cols
	)

Set the dimensions of the matrix.

Note that this does not change the underlying data, only it's interpretation.

Parameters

mat	Matrix
rows	New number of rows
cols	New number of columns

Returns

0 if successful