/usr/include/linbox/util/field-axpy.h is in liblinbox-dev 1.4.2-5build1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | /* linbox/util/field-axpy.h
* Copyright (C) 1999-2001 William J Turner,
* 2001 Bradford Hovinen
*
* Written by William J Turner <wjturner@math.ncsu.edu>,
* Bradford Hovinen <hovinen@cis.udel.edu>
*
* ========LICENCE========
* This file is part of the library LinBox.
*
* LinBox is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* ========LICENCE========
*/
#ifndef __LINBOX_util_field_axpy_H
#define __LINBOX_util_field_axpy_H
// Namespace in which all LinBox library code resides
namespace LinBox
{
/** FieldAXPY object.
*
* A fieldAXPY is an accumulator, allowing to add a number of field elements or products
* in an unnormalized state, delaying modular reduction as long as possible.
* This class containse a value y and wraps the operations <code>y = y + a * x</code> and
* <code>y = y + a</code>.
*
* This default instance does no optimization, no delayed modular reduction.
* Through the use of template specialization, objects of this type can
* be used to speed up operations such as vector dot product operations.
* In particular, for finite fields, dividing by the modulus and taking the remainder
* is expensive. In many cases, this can be postponed until the end of the
* dot product operation, thus vastly improving performance.
*
* FieldAXPY<Fld> is an assignable type. It is constructed from a field instance.
* The methods are mulacc(), accumulate(), operator=(), reset(), get(), and field().
* Of a const instance you can access get() and field().
* [Note: get() may renormalize the value, but it remains constant as a field element.]
*
* @param Field \ref LinBox @link Fields field@endlink
*/
template <class Field>
class FieldAXPY {
public:
/// Definition of element type
typedef typename Field::Element Element;
typedef Element Abnormal; // the type of the unnormalized values
/** Constructor.
* @param F field F in which arithmetic is done
*/
FieldAXPY (const Field &F) :
_field (&F)
{ field().assign(_y, field().zero); }
/** Copy constructor.
* @param faxpy
*/
FieldAXPY (const FieldAXPY<Field> &faxpy) :
_field (faxpy._field), _y (faxpy._y)
{}
/** Assignment operator
* @param faxpy
*/
FieldAXPY<Field> &operator = (const FieldAXPY<Field> &faxpy)
{
_field = faxpy.field();
_y = faxpy._y;
return *this;
}
/** Add a*x to y
* y += a*x.
* @param a constant reference to element a
* @param x constant reference to element x
*/
inline Element& mulacc (const Element &a, const Element &x)
{ return field().axpyin (_y, a, x); }
inline Element& accumulate (const Element &t)
{ return field().addin (_y, t); }
/** Retrieve y
*
* Performs the delayed modding out if necessary
*/
inline Element &get (Element &y) const { return y = _y; }
/// reset value to zero.
inline void reset() {
field().assign(_y,field().zero);
}
inline const Field& field() const { return *_field; }
protected:
/// Field in which arithmetic is done
const Field *_field;
/// Accumulator, unnormalized field element.
Abnormal _y;
}; // class FieldAXPY
} // namespace LinBox
#endif // __LINBOX_util_field_axpy_H
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