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Created page with "'''Home * Search * Node * Horizon Node''' '''Horizon nodes''' are nodes at depth zero, where a [[Quiescence Search|quiescence search]..."
'''[[Main Page|Home]] * [[Search]] * [[Node]] * Horizon Node'''
'''Horizon nodes''' are [[Node|nodes]] at [[Depth|depth]] zero, where a [[Quiescence Search|quiescence search]] is performed. The definition is taken from the papers of [[Ernst A. Heinz]] <ref>[[Ernst A. Heinz]] ('''1998'''). ''[http://people.csail.mit.edu/heinz/dt/node18.html Extended futility pruning]''. [[ICGA Journal#21_2|ICCA Journal, Vol. 21, No 2]], [http://people.csail.mit.edu/heinz/ps/ext_fut.ps.gz ps]</ref> depth == 0 nodes <ref>[https://www.stmintz.com/ccc/index.php?id=387518 Re: simple node definitions question] by [[Robert Hyatt]], [[Computer Chess Forums|CCC]], September 13, 2004</ref>. If the horizon node is an expected [[Node Types#CUT|Cut-Node]], confirmed by the evaluated [[Quiescence Search#StandPat|standing pat]] [[Score|score]] already greater or equal than [[Beta|beta]], the horizon node is a [[Leaf Node|leaf]] with the [[Lower Bound|lower bound]] score of beta ([[Fail-Hard|fail-hard]]) or the stand pat score ([[Fail-Soft|fail-soft]]). Otherwise, winning captures (or checks) may either cause a [[Beta-Cutoff|beta-cutoff]] or raise [[Alpha|alpha]] with an [[Exact Score|exact score]] at [[Node Types#PV|PV-Nodes]]. At expected [[Node Types#ALL|All-Nodes]] with evaluated score (far) below alpha, if no [[Tactical moves|tactical move]] is available, or due to [[Delta Pruning]] good enough to raise alpha, those [[Leaf Node|leaves]] return alpha ([[Fail-Hard|fail-hard]]) as an [[Upper Bound|upper bound]]. This may also appear, if this horizon node was not a leaf, since some captures were not pruned, but tried without raising alpha.
=Horizon Observatory=
[[FILE:Hoheward-Panorama.jpg|none|border|text-bottom|1024px]]
[https://de.wikipedia.org/wiki/Halde_Hoheward#Horizontobservatorium Horizon Observatory] (left) and horizontal [https://en.wikipedia.org/wiki/Sundial Sundial] with [https://en.wikipedia.org/wiki/Obelisk Obelisk] (right), [https://de.wikipedia.org/wiki/Halde_Hoheward Hoheward Spoil tip], [[Arts#IndustrialHeritageTrail|The Industrial Heritage Trail]] <ref>360–degree [https://en.wikipedia.org/wiki/Panorama Panorama] Photo by [https://commons.wikimedia.org/wiki/User:Panofreak Panofreak], April 12, 2009, [https://de.wikipedia.org/wiki/Halde_Hoheward Hoheward Spoil tip] in [https://en.wikipedia.org/wiki/Herten Herten], [https://en.wikipedia.org/wiki/North_Rhine-Westphalia North Rhine-Westphalia], Germany, [[Arts#IndustrialHeritageTrail|The Industrial Heritage Trail]] , view over the [https://en.wikipedia.org/wiki/Ruhr Ruhr area]. The observatory consists of a circular, flat surface of 88 m diameter, and a center forum lowered by 1.50 m with 35 m diameter with two arcs spanning [https://en.wikipedia.org/wiki/Meridian_%28astronomy%29 meridian] and [https://en.wikipedia.org/wiki/Celestial_equator celestial equator]. The horizon observatory is a modern version of [https://en.wikipedia.org/wiki/Prehistory prehistoric] [https://en.wikipedia.org/wiki/Stone_circle stone circles] and monuments such as [https://en.wikipedia.org/wiki/Stonehenge Stonehenge]. If the observer is located exactly in the lowered center, the plateau of the tip spreads in all directions like an artificial horizon, and with the help of bearing points the [https://en.wikipedia.org/wiki/Sunrise sunrise] and [https://en.wikipedia.org/wiki/Sunset sunset] at [https://en.wikipedia.org/wiki/Summer_solstice summer solstice], [https://en.wikipedia.org/wiki/Winter_solstice winter solstice] or [https://en.wikipedia.org/wiki/Equinox equinox] can be observed, by means of further bearing points also [https://en.wikipedia.org/wiki/Moon moon] solstices and the [https://en.wikipedia.org/wiki/Precession precession] of [https://en.wikipedia.org/wiki/Earth%27s_rotation Earth's axis] based on bearings of [https://en.wikipedia.org/wiki/Fixed_stars fixed stars]. The arcs divide the [https://en.wikipedia.org/wiki/Celestial_sphere celestial sphere] in eastern and western half as well as in [https://en.wikipedia.org/wiki/Northern_Hemisphere northern] and [https://en.wikipedia.org/wiki/Southern_Hemisphere southern hemisphere] and therefore serve as a [https://en.wikipedia.org/wiki/Solar_calendar solar calendar] at day, and at night, with the help of a [https://en.wikipedia.org/wiki/Luminous_paint self-luminous] scale as a guide of the [https://en.wikipedia.org/wiki/Night_sky night sky], [http://www.halden.ruhr/halden.html Halden im Ruhrgebiet] (German)</ref>
=See also=
* [[Frontier Nodes]]
* [[Horizon Effect]]
* [[Leaf Node]]
* [[Quiescent Node]]
=External Links=
* [[Videos#KarlJenkins|Karl Jenkins]] - [https://en.wikipedia.org/wiki/In_These_Stones_Horizons_Sing In These Stones Horizons Sing] (4th movement), [https://en.wikipedia.org/wiki/YouTube YouTube] Video
: Commissioned for the opening of [https://en.wikipedia.org/wiki/Wales_Millennium_Centre Wales Millennium Centre], first performed at its opening on November 29, 2004
: {{#evu:https://www.youtube.com/watch?v=u3HTUzSnEbs|alignment=left|valignment=top}}
=References=
<references />
'''[[Node|Up one Level]]'''
'''Horizon nodes''' are [[Node|nodes]] at [[Depth|depth]] zero, where a [[Quiescence Search|quiescence search]] is performed. The definition is taken from the papers of [[Ernst A. Heinz]] <ref>[[Ernst A. Heinz]] ('''1998'''). ''[http://people.csail.mit.edu/heinz/dt/node18.html Extended futility pruning]''. [[ICGA Journal#21_2|ICCA Journal, Vol. 21, No 2]], [http://people.csail.mit.edu/heinz/ps/ext_fut.ps.gz ps]</ref> depth == 0 nodes <ref>[https://www.stmintz.com/ccc/index.php?id=387518 Re: simple node definitions question] by [[Robert Hyatt]], [[Computer Chess Forums|CCC]], September 13, 2004</ref>. If the horizon node is an expected [[Node Types#CUT|Cut-Node]], confirmed by the evaluated [[Quiescence Search#StandPat|standing pat]] [[Score|score]] already greater or equal than [[Beta|beta]], the horizon node is a [[Leaf Node|leaf]] with the [[Lower Bound|lower bound]] score of beta ([[Fail-Hard|fail-hard]]) or the stand pat score ([[Fail-Soft|fail-soft]]). Otherwise, winning captures (or checks) may either cause a [[Beta-Cutoff|beta-cutoff]] or raise [[Alpha|alpha]] with an [[Exact Score|exact score]] at [[Node Types#PV|PV-Nodes]]. At expected [[Node Types#ALL|All-Nodes]] with evaluated score (far) below alpha, if no [[Tactical moves|tactical move]] is available, or due to [[Delta Pruning]] good enough to raise alpha, those [[Leaf Node|leaves]] return alpha ([[Fail-Hard|fail-hard]]) as an [[Upper Bound|upper bound]]. This may also appear, if this horizon node was not a leaf, since some captures were not pruned, but tried without raising alpha.
=Horizon Observatory=
[[FILE:Hoheward-Panorama.jpg|none|border|text-bottom|1024px]]
[https://de.wikipedia.org/wiki/Halde_Hoheward#Horizontobservatorium Horizon Observatory] (left) and horizontal [https://en.wikipedia.org/wiki/Sundial Sundial] with [https://en.wikipedia.org/wiki/Obelisk Obelisk] (right), [https://de.wikipedia.org/wiki/Halde_Hoheward Hoheward Spoil tip], [[Arts#IndustrialHeritageTrail|The Industrial Heritage Trail]] <ref>360–degree [https://en.wikipedia.org/wiki/Panorama Panorama] Photo by [https://commons.wikimedia.org/wiki/User:Panofreak Panofreak], April 12, 2009, [https://de.wikipedia.org/wiki/Halde_Hoheward Hoheward Spoil tip] in [https://en.wikipedia.org/wiki/Herten Herten], [https://en.wikipedia.org/wiki/North_Rhine-Westphalia North Rhine-Westphalia], Germany, [[Arts#IndustrialHeritageTrail|The Industrial Heritage Trail]] , view over the [https://en.wikipedia.org/wiki/Ruhr Ruhr area]. The observatory consists of a circular, flat surface of 88 m diameter, and a center forum lowered by 1.50 m with 35 m diameter with two arcs spanning [https://en.wikipedia.org/wiki/Meridian_%28astronomy%29 meridian] and [https://en.wikipedia.org/wiki/Celestial_equator celestial equator]. The horizon observatory is a modern version of [https://en.wikipedia.org/wiki/Prehistory prehistoric] [https://en.wikipedia.org/wiki/Stone_circle stone circles] and monuments such as [https://en.wikipedia.org/wiki/Stonehenge Stonehenge]. If the observer is located exactly in the lowered center, the plateau of the tip spreads in all directions like an artificial horizon, and with the help of bearing points the [https://en.wikipedia.org/wiki/Sunrise sunrise] and [https://en.wikipedia.org/wiki/Sunset sunset] at [https://en.wikipedia.org/wiki/Summer_solstice summer solstice], [https://en.wikipedia.org/wiki/Winter_solstice winter solstice] or [https://en.wikipedia.org/wiki/Equinox equinox] can be observed, by means of further bearing points also [https://en.wikipedia.org/wiki/Moon moon] solstices and the [https://en.wikipedia.org/wiki/Precession precession] of [https://en.wikipedia.org/wiki/Earth%27s_rotation Earth's axis] based on bearings of [https://en.wikipedia.org/wiki/Fixed_stars fixed stars]. The arcs divide the [https://en.wikipedia.org/wiki/Celestial_sphere celestial sphere] in eastern and western half as well as in [https://en.wikipedia.org/wiki/Northern_Hemisphere northern] and [https://en.wikipedia.org/wiki/Southern_Hemisphere southern hemisphere] and therefore serve as a [https://en.wikipedia.org/wiki/Solar_calendar solar calendar] at day, and at night, with the help of a [https://en.wikipedia.org/wiki/Luminous_paint self-luminous] scale as a guide of the [https://en.wikipedia.org/wiki/Night_sky night sky], [http://www.halden.ruhr/halden.html Halden im Ruhrgebiet] (German)</ref>
=See also=
* [[Frontier Nodes]]
* [[Horizon Effect]]
* [[Leaf Node]]
* [[Quiescent Node]]
=External Links=
* [[Videos#KarlJenkins|Karl Jenkins]] - [https://en.wikipedia.org/wiki/In_These_Stones_Horizons_Sing In These Stones Horizons Sing] (4th movement), [https://en.wikipedia.org/wiki/YouTube YouTube] Video
: Commissioned for the opening of [https://en.wikipedia.org/wiki/Wales_Millennium_Centre Wales Millennium Centre], first performed at its opening on November 29, 2004
: {{#evu:https://www.youtube.com/watch?v=u3HTUzSnEbs|alignment=left|valignment=top}}
=References=
<references />
'''[[Node|Up one Level]]'''
