mirror of
https://github.com/ruby/ruby.git
synced 2022-11-09 12:17:21 -05:00
75feee0968
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13944 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
148 lines
2.9 KiB
Ruby
148 lines
2.9 KiB
Ruby
# The Computer Language Shootout
|
|
# http://shootout.alioth.debian.org
|
|
#
|
|
# Optimized for Ruby by Jesse Millikan
|
|
# From version ported by Michael Neumann from the C gcc version,
|
|
# which was written by Christoph Bauer.
|
|
|
|
SOLAR_MASS = 4 * Math::PI**2
|
|
DAYS_PER_YEAR = 365.24
|
|
|
|
def _puts *args
|
|
end
|
|
|
|
class Planet
|
|
attr_accessor :x, :y, :z, :vx, :vy, :vz, :mass
|
|
|
|
def initialize(x, y, z, vx, vy, vz, mass)
|
|
@x, @y, @z = x, y, z
|
|
@vx, @vy, @vz = vx * DAYS_PER_YEAR, vy * DAYS_PER_YEAR, vz * DAYS_PER_YEAR
|
|
@mass = mass * SOLAR_MASS
|
|
end
|
|
|
|
def move_from_i(bodies, nbodies, dt, i)
|
|
while i < nbodies
|
|
b2 = bodies[i]
|
|
dx = @x - b2.x
|
|
dy = @y - b2.y
|
|
dz = @z - b2.z
|
|
|
|
distance = Math.sqrt(dx * dx + dy * dy + dz * dz)
|
|
mag = dt / (distance * distance * distance)
|
|
b_mass_mag, b2_mass_mag = @mass * mag, b2.mass * mag
|
|
|
|
@vx -= dx * b2_mass_mag
|
|
@vy -= dy * b2_mass_mag
|
|
@vz -= dz * b2_mass_mag
|
|
b2.vx += dx * b_mass_mag
|
|
b2.vy += dy * b_mass_mag
|
|
b2.vz += dz * b_mass_mag
|
|
i += 1
|
|
end
|
|
|
|
@x += dt * @vx
|
|
@y += dt * @vy
|
|
@z += dt * @vz
|
|
end
|
|
end
|
|
|
|
def energy(bodies)
|
|
e = 0.0
|
|
nbodies = bodies.size
|
|
|
|
for i in 0 ... nbodies
|
|
b = bodies[i]
|
|
e += 0.5 * b.mass * (b.vx * b.vx + b.vy * b.vy + b.vz * b.vz)
|
|
for j in (i + 1) ... nbodies
|
|
b2 = bodies[j]
|
|
dx = b.x - b2.x
|
|
dy = b.y - b2.y
|
|
dz = b.z - b2.z
|
|
distance = Math.sqrt(dx * dx + dy * dy + dz * dz)
|
|
e -= (b.mass * b2.mass) / distance
|
|
end
|
|
end
|
|
e
|
|
end
|
|
|
|
def offset_momentum(bodies)
|
|
px, py, pz = 0.0, 0.0, 0.0
|
|
|
|
for b in bodies
|
|
m = b.mass
|
|
px += b.vx * m
|
|
py += b.vy * m
|
|
pz += b.vz * m
|
|
end
|
|
|
|
b = bodies[0]
|
|
b.vx = - px / SOLAR_MASS
|
|
b.vy = - py / SOLAR_MASS
|
|
b.vz = - pz / SOLAR_MASS
|
|
end
|
|
|
|
BODIES = [
|
|
# sun
|
|
Planet.new(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0),
|
|
|
|
# jupiter
|
|
Planet.new(
|
|
4.84143144246472090e+00,
|
|
-1.16032004402742839e+00,
|
|
-1.03622044471123109e-01,
|
|
1.66007664274403694e-03,
|
|
7.69901118419740425e-03,
|
|
-6.90460016972063023e-05,
|
|
9.54791938424326609e-04),
|
|
|
|
# saturn
|
|
Planet.new(
|
|
8.34336671824457987e+00,
|
|
4.12479856412430479e+00,
|
|
-4.03523417114321381e-01,
|
|
-2.76742510726862411e-03,
|
|
4.99852801234917238e-03,
|
|
2.30417297573763929e-05,
|
|
2.85885980666130812e-04),
|
|
|
|
# uranus
|
|
Planet.new(
|
|
1.28943695621391310e+01,
|
|
-1.51111514016986312e+01,
|
|
-2.23307578892655734e-01,
|
|
2.96460137564761618e-03,
|
|
2.37847173959480950e-03,
|
|
-2.96589568540237556e-05,
|
|
4.36624404335156298e-05),
|
|
|
|
# neptune
|
|
Planet.new(
|
|
1.53796971148509165e+01,
|
|
-2.59193146099879641e+01,
|
|
1.79258772950371181e-01,
|
|
2.68067772490389322e-03,
|
|
1.62824170038242295e-03,
|
|
-9.51592254519715870e-05,
|
|
5.15138902046611451e-05)
|
|
]
|
|
|
|
init = 200_000 # ARGV[0]
|
|
n = Integer(init)
|
|
|
|
offset_momentum(BODIES)
|
|
|
|
puts "%.9f" % energy(BODIES)
|
|
|
|
nbodies = BODIES.size
|
|
dt = 0.01
|
|
|
|
n.times do
|
|
i = 0
|
|
while i < nbodies
|
|
b = BODIES[i]
|
|
b.move_from_i(BODIES, nbodies, dt, i + 1)
|
|
i += 1
|
|
end
|
|
end
|
|
|
|
puts "%.9f" % energy(BODIES)
|