mcb::spvecfp Class Reference

A sparse vector with elements in . More...

#include <spvecfp.h>

Public Member Functions
	spvecfp ()
	spvecfp (const ptype &p)
	spvecfp (const spvecfp &a)
	~spvecfp ()
void	reset (const ptype &p)
spvecfp	operator- () const
ptype	operator* (const spvecfp &a) const
spvecfp	operator+ (const spvecfp &a) const
spvecfp	operator* (const ptype &a)
spvecfp &	operator+= (const spvecfp &a)
spvecfp &	operator-= (const spvecfp &a)
void	print (std::ostream &o) const
void	append (indextype index, const ptype &value)
void	sort ()
bool	empty () const
void	clear ()
indextype	size () const
ptype	pvalue () const
list_item	first () const
list_item	last () const
list_item	succ (list_item it) const
list_item	pred (list_item it) const
indextype	index (list_item it) const
ptype	inf (list_item it) const

Detailed Description

A sparse vector with elements in .

This class implements a sparse vector with elements in . The supported operations are limited to those required by the cycle basis algorithms.

The internal representation is a list of tuples, one for each non-zero entry of the sparse vector. Each tuple contains two integers, the index of the non-zero entry and its value. This entries are supposed to be sorted in order for the various binary operators to work properly. The function append does not ensure this, it is up to the user to make sure that the correct order is maintained.

Remarks

Indices are between and where is the length of the vector.

Date

2005

Author

Dimitrios Michail

Constructor & Destructor Documentation

mcb::spvecfp::spvecfp

(

)

Default Constructor

mcb::spvecfp::spvecfp

(

const ptype &

p

)

Constructor

Parameters

p	Prime number.

mcb::spvecfp::spvecfp

(

const spvecfp &

a

)

Copy constructor

mcb::spvecfp::~spvecfp

(

)

Descructor

Member Function Documentation

void mcb::spvecfp::append	(	indextype	index,
		const ptype &	value
	)

Append an entry to the sparse vector. The internal representation is a list of sorted entries by index. This procedure does not enforce this order, it simply appends the new entry. Use wisely.

Parameters

index	Index of the new element to append.
value	The value of the new element to append.

Remarks

No attempt to preserve correct sorted order is done. All elements in the vector must have index values less that the new element's for the resulting sparse vector to be valid.

void mcb::spvecfp::clear

(

)

Make all elements zero.

bool mcb::spvecfp::empty

(

)

const

Check if the vector is empty, all elements are zero.

Returns

True if empty, false otherwise.

list_item mcb::spvecfp::first

(

)

const

Get the first item of the internal representation of the vector.

Returns

The first item of the internal representation.

indextype mcb::spvecfp::index

(

list_item

it

)

const

Get the index of an item.

Returns

The index of an item.

ptype mcb::spvecfp::inf

(

list_item

it

)

const

Get the information of an item.

Returns

The information of an item.

list_item mcb::spvecfp::last

(

)

const

Get the last item of the internal representation of the vector.

Returns

The last item of the internal representation.

ptype mcb::spvecfp::operator*

(

const spvecfp &

a

)

const

Compute the inner product of two vectors.

Parameters

a	A sparse vector.

Returns

The inner product of this vector and a.

spvecfp mcb::spvecfp::operator*

(

const ptype &

a

)

Compute the product with a constant.

Parameters

a	A constant.

Returns

The product of the current vector with a constant.

spvecfp mcb::spvecfp::operator+

(

const spvecfp &

a

)

const

Add two vectors.

Parameters

a	A sparse vector.

Returns

The sum of this vector and a.

spvecfp& mcb::spvecfp::operator+=

(

const spvecfp &

a

)

Add a vector to the current vector.

Parameters

a	A sparse vector a.

Returns

The current vector after adding a.

spvecfp mcb::spvecfp::operator-

(

)

const

Negate the current sparse vector.

Returns

A new vector corresponding to current vector negated.

spvecfp& mcb::spvecfp::operator-=

(

const spvecfp &

a

)

Subtract a vector from the current vector.

Parameters

a	A sparse vector a.

Returns

The current vector after subtracting a.

list_item mcb::spvecfp::pred

(

list_item

it

)

const

Get the predecessor of an item of the interal representation.

Parameters

it

An item.

Returns

The predecessor of it.

void mcb::spvecfp::print

(

std::ostream &

o

)

const

Print the vector to a stream.

Parameters

o	The stream to print at.

ptype mcb::spvecfp::pvalue

(

)

const

Get the value of the prime p.

Returns

The value of the prime p.

void mcb::spvecfp::reset

(

const ptype &

p

)

Clear the vector and reinitialize it.

Parameters

p	Prime number.

indextype mcb::spvecfp::size

(

)

const

Get the number of non-zero entries.

Returns

The number of non-zero entries in the vector.

void mcb::spvecfp::sort

(

)

Sort the internal representation of the sparse vector. This operation ensures a correct representation after its call. Should not be necessary unless append was called in wrong order.

list_item mcb::spvecfp::succ

(

list_item

it

)

const

Get the successor of an item of the internal representation.

Parameters

it

An item.

Returns

The successor of it.