Issues with the Interval Library

[dduffy@…]

I am trying to compile some examples; in particular, the trigonometric, hyperbolic trig and transendental (exp, log!!)functions don't compile with default roudning policy (see file I included). It's a kind of show-stopper.

Some user requests as well are:

1. Instead of bool when comparing interval, use TriBool (a result can be _indeterminate_)

2. Interval is missing midpoint() (same as median()).

3. Interval analysis is highly specialised; more user examples would be very welcome.

I have the books by R.E. Moore but it takes some time to map his results to Interval.

best regards

Daniel

Code

TestInterval101.cpp Tests for Interval arithmetic. (C) Datasim Education BV 2009-2011

#include <boost/numeric/interval.hpp>

template<class T, class Policies> std::ostream &operator<<(std::ostream &os,

const boost::numeric::interval<T, Policies> &x) {

os << "[" << x.lower() << ", " << x.upper() << "]"; return os;

}

typedef boost::numeric::interval<double> Range;

int main() {

using namespace boost::numeric;

Create and manipulate some numbers. Range r1(0.0, 1,0);

Range r2(-10.0, 20.0); Range r3(20.8, 44.9);

double t = 2.0; r1 += t; r1 -= t; r1 *= t; r1 /= t;

Range rTmp(2.0, 3.0); r1 += rTmp; r1 -= rTmp; r1 *= rTmp; r1 /= rTmp;

Numeric operations. Range r4 = r1 + r2; Range r5 = r1 - r2; Range r6 = r1 * r2; Range r7 = r1 / r2;

More numeric operations. t = 3.0; r4 = r1 + t; r5 = r1 - t; r6 = r1 * t; r7 = r1 / t;

Algebraic functions. r4 = abs(r1); r5 = sqrt(r2); r6 = square(r3); r7 = pow(r1, 2); r1^{2 Range r8 = nth_root(r1, 4);}

NONE COMPILES Transcendental functions

r4 = exp(r1); boost::numeric::interval<double, boost::numeric::interval_lib::default_policies<double> > myI; myI = boost::numeric::exp(myI);

r5 = log(r2);

Trigonometric functions

/* r4 = sin(r1);

r5 = cos(r1); r6 = tan(r1); r7 = asin(r2); r7 = acos(r2); r7 = atan(r2);

Hyperbolic trigonometric functions r4 = sinh(r1); r5 = cosh(r1); r6 = tanh(r1); r7 = asinh(r2); r8 = acosh(r2); r6 = atanh(r2);*/

return 0;

}

[anonymous]

I (Daniel Duffy) discovered the cause: Interval does not provide default implementation of up and down rounding policies. As a POC, I created a simple policy that I tested with interval Newton Raphson

[anonymous]

class DDPolicy : public rounded_math<double> { public:

double exp_up(double x) { return ::exp(x);} double exp_down(double x) { return ::exp(x);}

etc.

};

Transcendental functions boost::numeric::interval<double, policies<DDPolicy, checking_strict<double> > > rA; boost::numeric::interval<double, policies<DDPolicy, checking_strict<double> > > rB;

rB = exp(rA);

[viboes]

How is this a showstopper?

[anonymous]

Well. IMO is still a show stopper and it has not been solved.

Daniel Duffy

[anonymous]

It's a show stopper because you can't <cmath> functionality on Interval. But +, -, * and / do work.

[anonymous]

We are now 4 years on. You conventiently changed status to PROBLEM...

Has this show stopper been resolved? IMO it's easy to fix.

thanks

Daniel J. Duffy

[anonymous]

Anybody with a solution??