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#include <libnr/nr-point-fns.h>
#include <isnan.h>
using NR::Point;
/** Compute the L infinity, or maximum, norm of \a p. */
NR::Coord NR::LInfty(Point const &p) {
NR::Coord const a(fabs(p[0]));
NR::Coord const b(fabs(p[1]));
return ( a < b || isNaN(b)
? b
: a );
}
/** Returns true iff p is a zero vector, i.e.\ Point(0, 0).
*
* (NaN is considered non-zero.)
*/
bool
NR::is_zero(Point const &p)
{
return ( p[0] == 0 &&
p[1] == 0 );
}
bool
NR::is_unit_vector(Point const &p)
{
return fabs(1.0 - L2(p)) <= 1e-4;
/* The tolerance of 1e-4 is somewhat arbitrary. NR::Point::normalize is believed to return
points well within this tolerance. I'm not aware of any callers that want a small
tolerance; most callers would be ok with a tolerance of 0.25. */
}
NR::Coord NR::atan2(Point const p) {
return std::atan2(p[NR::Y], p[NR::X]);
}
/** Returns a version of \a a scaled to be a unit vector (within rounding error).
*
* The current version tries to handle infinite coordinates gracefully,
* but it's not clear that any callers need that.
*
* \pre a != Point(0, 0).
* \pre Neither coordinate is NaN.
* \post L2(ret) very near 1.0.
*/
Point NR::unit_vector(Point const &a)
{
Point ret(a);
ret.normalize();
return ret;
}
NR::Point abs(NR::Point const &b)
{
NR::Point ret;
for ( int i = 0 ; i < 2 ; i++ ) {
ret[i] = fabs(b[i]);
}
return ret;
}
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
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