/usr/include/opengm/operations/logsumexp.hxx is in libopengm-dev 2.3.6+20160905-1build2.
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 | #pragma once
#ifndef OPENGM_OPERATIONS_LOGSUMEXP_HXX
#define OPENGM_OPERATIONS_LOGSUMEXP_HXX
#include "adder.hxx"
#include <cmath>
namespace opengm {
/// Logsumexp (addition in log space) as a unary accumulation
///
/// \ingroup operators
struct Logsumexp
{
/// neutral element (with return)
template<class T>
static T neutral()
{ return -std::numeric_limits<T>::infinity(); }
/// neutral element (call by reference)
template<class T>
static void neutral(T& out)
{ out = -std::numeric_limits<T>::infinity(); }
/// inverse neutral element (with return)
template<class T>
static T ineutral()
{ return std::numeric_limits<T>::infinity(); }
/// inverse neutral element (call by reference)
template<class T>
static void ineutral(T& out)
{ out = std::numeric_limits<T>::infinity(); }
/// operation (in-place)
template<class T1, class T2>
static void op(const T1& in1, T2& out)
// { out = log(exp(out) + exp(in1)); }
{
T2 theMax = std::max(in1, out);
T2 theMin = std::min(in1, out);
out = theMax + log(1 + exp(theMin - theMax)); // numerically better
}
/// operation (not in-place)
template<class T1,class T2,class T3>
static void op(const T1 in1, const T2 in2, T3& out)
// { out = log(exp(in1) + exp(in2)); }
{
T2 theMax = std::max(in1, out);
T2 theMin = std::min(in1, out);
out = theMax + log(1 + exp(theMin - theMax)); // numerically better
}
/// inverse operation (in-place)
template<class T1, class T2>
static void iop(const T1& in1, T2& out)
// { out - in1; } // reference implementation has no effect?
{ throw "not implemented"; }
/// inverse operation (call by reference)
template<class T1,class T2,class T3>
static void iop(const T1 in1, const T2 in2, T3& out)
{ out = log(exp(in1) - exp(in2)); }
/// bool operation flag
static bool hasbop()
{ return false; }
/// \obsolete inverse boolean operation
/// boolean operation (obsolete)
template<class T>
static bool bop(const T& in1, const T& in2)
{ return false; }
/// \obsolete inverse boolean operation
/// inverse boolean operation (obsolete)
template<class T>
static bool ibop(const T& in1, const T& in2)
{ return false; }
};
} // namespace opengm
#endif // #ifndef OPENGM_OPERATIONS_INTEGRATOR_HXX
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