/usr/include/linbox/blackbox/hilbert.h is in liblinbox-dev 1.1.6~rc0-4.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | /* linbox/blackbox/hilbert.h
* Copyright (C) 2006 John P. May, B. David Saunders
*
* Written by John P. May <jpmay@cis.udel.edu>,
* B. David Saunders <saunders@cis.udel.edu>
*
* ------------------------------------
* The original hilbert.h, providing one of the first blackbox examples, but not using the JIT feature,
* was written by Will Turner.
*
* See COPYING for license information.
*/
#ifndef HILBERT_H_
#define HILBERT_H_
#include<vector>
#include<linbox/blackbox/jit-matrix.h>
namespace LinBox {
/// The object needed to build a Hilbert matrix as a JIT matrix
template<typename _Field>
class Hilbert_JIT_Entry {
public:
typedef _Field Field;
typedef typename _Field::Element Element;
/// set up vector of 1/(i+1)
Hilbert_JIT_Entry(Field& F, size_t m, size_t n);
/// return 1/(i+j+2), zero based indexing.
Element& operator()(Element &entry, size_t i, size_t j) const
{ return entry = _H[i+j+1]; }
private:
std::vector<Element> _H;
}; // Hilbert_JIT_Entry
template<typename _Field>
Hilbert_JIT_Entry<_Field>::Hilbert_JIT_Entry(_Field& F, size_t m, size_t n) {
Element temp, one;
F.init(one, 1);
F.init(temp, 0);
_H = std::vector<Element>(m+n, temp);
typename std::vector<Element>::iterator iter;
// the ith entry of _H = 1/(i+1)
for (iter=_H.begin(); iter != _H.end(); iter++) {
F.addin(temp, one);
F.inv(*iter, temp);
}
}//constructor
/** \brief Example of a blackbox that is space efficient, though not time efficient.
\ingroup blackbox
Blackbox for the matrix whose i,j entry is 1/(i+j), i in 1..n, j in 1..n.
*/
template<typename _Field>
class Hilbert : public JIT_Matrix<_Field, Hilbert_JIT_Entry<_Field> > {
public:
/** Constructor from field and size.
* @param n size_t integer number of rows and columns of matrix.
*/
Hilbert(_Field& F, size_t n) :
JIT_Matrix<_Field, Hilbert_JIT_Entry<_Field> >(F, n, n, Hilbert_JIT_Entry<_Field>(F, n, n))
{};
};
}//LinBox Namespace
#endif
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