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/* This file is part of the Gudhi Library. The Gudhi library
* (Geometric Understanding in Higher Dimensions) is a generic C++
* library for computational topology.
*
* Author(s): Pawel Dlotko
*
* Copyright (C) 2017 Swansea University, UK
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef WRITING_PERSISTENCE_TO_FILE_H_
#define WRITING_PERSISTENCE_TO_FILE_H_
#include <iostream>
#include <string>
#include <limits>
namespace Gudhi {
/**
* This is a class to store persistence intervals. Its main purpose is to
* exchange data in between different packages and provide unified way
* of writing a collection of persistence intervals to file.
**/
template <typename Filtration_type, typename Coefficient_field>
class Persistence_interval_common {
public:
/**
* Constructor taking as an input birth and death of the pair.
**/
Persistence_interval_common(Filtration_type birth, Filtration_type death)
: birth_(birth),
death_(death),
dimension_(std::numeric_limits<unsigned>::max()),
arith_element_(std::numeric_limits<Coefficient_field>::max()) {}
/**
* Constructor taking as an input birth, death and dimension of the pair.
**/
Persistence_interval_common(Filtration_type birth, Filtration_type death, unsigned dim)
: birth_(birth), death_(death), dimension_(dim), arith_element_(std::numeric_limits<Coefficient_field>::max()) {}
/**
* Constructor taking as an input birth, death, dimension of the pair as well
* as the number p such that this interval is present over Z_p field.
**/
Persistence_interval_common(Filtration_type birth, Filtration_type death, unsigned dim, Coefficient_field field)
: birth_(birth), death_(death), dimension_(dim), arith_element_(field) {}
/**
* Operator to compare two persistence pairs. During the comparision all the
* fields: birth, death, dimensiona and arith_element_ are taken into account
* and they all have to be equal for two pairs to be equal.
**/
bool operator==(const Persistence_interval_common& i2) const {
return ((this->birth_ == i2.birth_) && (this->death_ == i2.death_) && (this->dimension_ == i2.dimension_) &&
(this->arith_element_ == i2.arith_element_));
}
/**
* Check if two persistence paris are not equal.
**/
bool operator!=(const Persistence_interval_common& i2) const { return (!((*this) == i2)); }
/**
* Operator to compare objects of a type Persistence_interval_common.
* One intervals is smaller than the other if it has lower persistence.
* Note that this operator do not take Arith_element into account when doing comparisions.
**/
bool operator<(const Persistence_interval_common& i2) const {
return fabs(this->death_ - this->birth_) < fabs(i2.death_ - i2.birth_);
}
friend std::ostream& operator<<(std::ostream& out, const Persistence_interval_common& it) {
if (it.arith_element_ != std::numeric_limits<Coefficient_field>::max()) {
out << it.arith_element_ << " ";
}
if (it.dimension_ != std::numeric_limits<unsigned>::max()) {
out << it.dimension_ << " ";
}
out << it.birth_ << " " << it.death_ << " ";
return out;
}
private:
Filtration_type birth_;
Filtration_type death_;
unsigned dimension_;
Coefficient_field arith_element_;
};
/**
* This function write a vector<Persistence_interval_common> to a stream
**/
template <typename Persistence_interval_range>
void write_persistence_intervals_to_stream(const Persistence_interval_range& intervals,
std::ostream& out = std::cout) {
for (auto interval : intervals) {
out << interval << "\n";
}
}
} // namespace Gudhi
#endif // WRITING_PERSISTENCE_TO_FILE_H_
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