diff options
Diffstat (limited to 'lua_benchmark/tests/Lua-Benchmarks/n-body.lua')
| -rw-r--r-- | lua_benchmark/tests/Lua-Benchmarks/n-body.lua | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/lua_benchmark/tests/Lua-Benchmarks/n-body.lua b/lua_benchmark/tests/Lua-Benchmarks/n-body.lua new file mode 100644 index 0000000..40cee46 --- /dev/null +++ b/lua_benchmark/tests/Lua-Benchmarks/n-body.lua @@ -0,0 +1,121 @@ +-- The Computer Language Benchmarks Game +-- http://benchmarksgame.alioth.debian.org/ +-- contributed by Mike Pall +-- modified by Geoff Leyland +-- modified by Mario Pernici + +sun = {} +jupiter = {} +saturn = {} +uranus = {} +neptune = {} + +local sqrt = math.sqrt + +local PI = 3.141592653589793 +local SOLAR_MASS = 4 * PI * PI +local DAYS_PER_YEAR = 365.24 +sun.x = 0.0 +sun.y = 0.0 +sun.z = 0.0 +sun.vx = 0.0 +sun.vy = 0.0 +sun.vz = 0.0 +sun.mass = SOLAR_MASS +jupiter.x = 4.84143144246472090e+00 +jupiter.y = -1.16032004402742839e+00 +jupiter.z = -1.03622044471123109e-01 +jupiter.vx = 1.66007664274403694e-03 * DAYS_PER_YEAR +jupiter.vy = 7.69901118419740425e-03 * DAYS_PER_YEAR +jupiter.vz = -6.90460016972063023e-05 * DAYS_PER_YEAR +jupiter.mass = 9.54791938424326609e-04 * SOLAR_MASS +saturn.x = 8.34336671824457987e+00 +saturn.y = 4.12479856412430479e+00 +saturn.z = -4.03523417114321381e-01 +saturn.vx = -2.76742510726862411e-03 * DAYS_PER_YEAR +saturn.vy = 4.99852801234917238e-03 * DAYS_PER_YEAR +saturn.vz = 2.30417297573763929e-05 * DAYS_PER_YEAR +saturn.mass = 2.85885980666130812e-04 * SOLAR_MASS +uranus.x = 1.28943695621391310e+01 +uranus.y = -1.51111514016986312e+01 +uranus.z = -2.23307578892655734e-01 +uranus.vx = 2.96460137564761618e-03 * DAYS_PER_YEAR +uranus.vy = 2.37847173959480950e-03 * DAYS_PER_YEAR +uranus.vz = -2.96589568540237556e-05 * DAYS_PER_YEAR +uranus.mass = 4.36624404335156298e-05 * SOLAR_MASS +neptune.x = 1.53796971148509165e+01 +neptune.y = -2.59193146099879641e+01 +neptune.z = 1.79258772950371181e-01 +neptune.vx = 2.68067772490389322e-03 * DAYS_PER_YEAR +neptune.vy = 1.62824170038242295e-03 * DAYS_PER_YEAR +neptune.vz = -9.51592254519715870e-05 * DAYS_PER_YEAR +neptune.mass = 5.15138902046611451e-05 * SOLAR_MASS + +local bodies = {sun,jupiter,saturn,uranus,neptune} + +local function advance(bodies, nbody, dt) + for i=1,nbody do + local bi = bodies[i] + local bix, biy, biz, bimass = bi.x, bi.y, bi.z, bi.mass + local bivx, bivy, bivz = bi.vx, bi.vy, bi.vz + for j=i+1,nbody do + local bj = bodies[j] + local dx, dy, dz = bix-bj.x, biy-bj.y, biz-bj.z + local dist2 = dx*dx + dy*dy + dz*dz + local mag = sqrt(dist2) + mag = dt / (mag * dist2) + local bm = bj.mass*mag + bivx = bivx - (dx * bm) + bivy = bivy - (dy * bm) + bivz = bivz - (dz * bm) + bm = bimass*mag + bj.vx = bj.vx + (dx * bm) + bj.vy = bj.vy + (dy * bm) + bj.vz = bj.vz + (dz * bm) + end + bi.vx = bivx + bi.vy = bivy + bi.vz = bivz + bi.x = bix + dt * bivx + bi.y = biy + dt * bivy + bi.z = biz + dt * bivz + end +end + +local function energy(bodies, nbody) + local e = 0 + for i=1,nbody do + local bi = bodies[i] + local vx, vy, vz, bim = bi.vx, bi.vy, bi.vz, bi.mass + e = e + (0.5 * bim * (vx*vx + vy*vy + vz*vz)) + for j=i+1,nbody do + local bj = bodies[j] + local dx, dy, dz = bi.x-bj.x, bi.y-bj.y, bi.z-bj.z + local distance = sqrt(dx*dx + dy*dy + dz*dz) + e = e - ((bim * bj.mass) / distance) + end + end + return e +end + +local function offsetMomentum(b, nbody) + local px, py, pz = 0, 0, 0 + for i=1,nbody do + local bi = b[i] + local bim = bi.mass + px = px + (bi.vx * bim) + py = py + (bi.vy * bim) + pz = pz + (bi.vz * bim) + end + b[1].vx = -px / SOLAR_MASS + b[1].vy = -py / SOLAR_MASS + b[1].vz = -pz / SOLAR_MASS +end + +local N = tonumber(arg and arg[1]) or 1000 +local nbody = #bodies + +offsetMomentum(bodies, nbody) +io.write( string.format("%0.9f",energy(bodies, nbody)), "\n") +for i=1,N do advance(bodies, nbody, 0.01) end +io.write( string.format("%0.9f",energy(bodies, nbody)), "\n") |