! Copyright (C) 2008 Slava Pestov. ! See http://factorcode.org/license.txt for BSD license. USING: accessors float-arrays fry kernel locals make math math.constants math.functions math.vectors prettyprint sequences hints arrays ; IN: benchmark.nbody : solar-mass 4 pi sq * ; inline : days-per-year 365.24 ; inline TUPLE: body { location float-array } { velocity float-array } { mass float } ; : ( -- body ) body new ; inline : ( -- body ) F{ 4.84143144246472090e+00 -1.16032004402742839e+00 -1.03622044471123109e-01 } >>location F{ 1.66007664274403694e-03 7.69901118419740425e-03 -6.90460016972063023e-05 } days-per-year v*n >>velocity 9.54791938424326609e-04 solar-mass * >>mass ; : ( -- body ) F{ 8.34336671824457987e+00 4.12479856412430479e+00 -4.03523417114321381e-01 } >>location F{ -2.76742510726862411e-03 4.99852801234917238e-03 2.30417297573763929e-05 } days-per-year v*n >>velocity 2.85885980666130812e-04 solar-mass * >>mass ; : ( -- body ) F{ 1.28943695621391310e+01 -1.51111514016986312e+01 -2.23307578892655734e-01 } >>location F{ 2.96460137564761618e-03 2.37847173959480950e-03 -2.96589568540237556e-05 } days-per-year v*n >>velocity 4.36624404335156298e-05 solar-mass * >>mass ; : ( -- body ) F{ 1.53796971148509165e+01 -2.59193146099879641e+01 1.79258772950371181e-01 } >>location F{ 2.68067772490389322e-03 1.62824170038242295e-03 -9.51592254519715870e-05 } days-per-year v*n >>velocity 5.15138902046611451e-05 solar-mass * >>mass ; : ( -- body ) solar-mass >>mass F{ 0 0 0 } >>location F{ 0 0 0 } >>velocity ; : offset-momentum ( body offset -- body ) vneg solar-mass v/n >>velocity ; inline TUPLE: nbody-system { bodies array } ; : init-bodies ( bodies -- ) [ first ] [ F{ 0 0 0 } [ [ velocity>> ] [ mass>> ] bi v*n v+ ] reduce ] bi offset-momentum drop ; inline : ( -- system ) nbody-system new [ , , , , , ] { } make >>bodies dup bodies>> init-bodies ; inline :: each-pair ( bodies pair-quot: ( other-body body -- ) each-quot: ( body -- ) -- ) bodies [| body i | body each-quot call bodies i 1+ tail-slice [ body pair-quot call ] each ] each-index ; inline : update-position ( body dt -- ) [ dup velocity>> ] dip '[ _ _ v*n v+ ] change-location drop ; : mag ( dt body other-body -- mag d ) [ location>> ] bi@ v- [ norm-sq dup sqrt * / ] keep ; inline :: update-velocity ( other-body body dt -- ) dt body other-body mag [ [ body ] 2dip '[ other-body mass>> _ * _ n*v v- ] change-velocity drop ] [ [ other-body ] 2dip '[ body mass>> _ * _ n*v v+ ] change-velocity drop ] 2bi ; : advance ( system dt -- ) [ bodies>> ] dip [ '[ _ update-velocity ] [ drop ] each-pair ] [ '[ _ update-position ] each ] 2bi ; inline : inertia ( body -- e ) [ mass>> ] [ velocity>> norm-sq ] bi * 0.5 * ; : newton's-law ( other-body body -- e ) [ [ mass>> ] bi@ * ] [ [ location>> ] bi@ distance ] 2bi / ; : energy ( system -- x ) [ 0.0 ] dip bodies>> [ newton's-law - ] [ inertia + ] each-pair ; inline : nbody-main ( n -- ) [ energy . ] [ '[ _ 0.01 advance ] times ] [ energy . ] tri ; HINTS: update-position body float ; HINTS: update-velocity body body float ; HINTS: inertia body ; HINTS: newton's-law body body ;