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Diffstat (limited to 'test/bench/nbody.go')
| -rw-r--r-- | test/bench/nbody.go | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/test/bench/nbody.go b/test/bench/nbody.go deleted file mode 100644 index e9f4517e8..000000000 --- a/test/bench/nbody.go +++ /dev/null @@ -1,177 +0,0 @@ -/* -Redistribution and use in source and binary forms, with or without -modification, are permitted provided that the following conditions are met: - - * Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - - * Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer in the - documentation and/or other materials provided with the distribution. - - * Neither the name of "The Computer Language Benchmarks Game" nor the - name of "The Computer Language Shootout Benchmarks" nor the names of - its contributors may be used to endorse or promote products derived - from this software without specific prior written permission. - -THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" -AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE -IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE -ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE -LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR -CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF -SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS -INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN -CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) -ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -POSSIBILITY OF SUCH DAMAGE. -*/ - -/* The Computer Language Benchmarks Game - * http://shootout.alioth.debian.org/ - * - * contributed by The Go Authors. - * based on C program by Christoph Bauer - */ - -package main - -import ( - "flag" - "fmt" - "math" -) - -var n = flag.Int("n", 1000, "number of iterations") - -type Body struct { - x, y, z, vx, vy, vz, mass float64 -} - -const ( - solarMass = 4 * math.Pi * math.Pi - daysPerYear = 365.24 -) - -func (b *Body) offsetMomentum(px, py, pz float64) { - b.vx = -px / solarMass - b.vy = -py / solarMass - b.vz = -pz / solarMass -} - -type System []*Body - -func NewSystem(body []Body) System { - n := make(System, len(body)) - for i := 0; i < len(body); i++ { - n[i] = new(Body) // copy to avoid overwriting the inputs - *n[i] = body[i] - } - var px, py, pz float64 - for _, body := range n { - px += body.vx * body.mass - py += body.vy * body.mass - pz += body.vz * body.mass - } - n[0].offsetMomentum(px, py, pz) - return n -} - -func (sys System) energy() float64 { - var e float64 - for i, body := range sys { - e += 0.5 * body.mass * - (body.vx*body.vx + body.vy*body.vy + body.vz*body.vz) - for j := i + 1; j < len(sys); j++ { - body2 := sys[j] - dx := body.x - body2.x - dy := body.y - body2.y - dz := body.z - body2.z - distance := math.Sqrt(dx*dx + dy*dy + dz*dz) - e -= (body.mass * body2.mass) / distance - } - } - return e -} - -func (sys System) advance(dt float64) { - for i, body := range sys { - for j := i + 1; j < len(sys); j++ { - body2 := sys[j] - dx := body.x - body2.x - dy := body.y - body2.y - dz := body.z - body2.z - - dSquared := dx*dx + dy*dy + dz*dz - distance := math.Sqrt(dSquared) - mag := dt / (dSquared * distance) - - body.vx -= dx * body2.mass * mag - body.vy -= dy * body2.mass * mag - body.vz -= dz * body2.mass * mag - - body2.vx += dx * body.mass * mag - body2.vy += dy * body.mass * mag - body2.vz += dz * body.mass * mag - } - } - - for _, body := range sys { - body.x += dt * body.vx - body.y += dt * body.vy - body.z += dt * body.vz - } -} - -var ( - jupiter = Body{ - x: 4.84143144246472090e+00, - y: -1.16032004402742839e+00, - z: -1.03622044471123109e-01, - vx: 1.66007664274403694e-03 * daysPerYear, - vy: 7.69901118419740425e-03 * daysPerYear, - vz: -6.90460016972063023e-05 * daysPerYear, - mass: 9.54791938424326609e-04 * solarMass, - } - saturn = Body{ - x: 8.34336671824457987e+00, - y: 4.12479856412430479e+00, - z: -4.03523417114321381e-01, - vx: -2.76742510726862411e-03 * daysPerYear, - vy: 4.99852801234917238e-03 * daysPerYear, - vz: 2.30417297573763929e-05 * daysPerYear, - mass: 2.85885980666130812e-04 * solarMass, - } - uranus = Body{ - x: 1.28943695621391310e+01, - y: -1.51111514016986312e+01, - z: -2.23307578892655734e-01, - vx: 2.96460137564761618e-03 * daysPerYear, - vy: 2.37847173959480950e-03 * daysPerYear, - vz: -2.96589568540237556e-05 * daysPerYear, - mass: 4.36624404335156298e-05 * solarMass, - } - neptune = Body{ - x: 1.53796971148509165e+01, - y: -2.59193146099879641e+01, - z: 1.79258772950371181e-01, - vx: 2.68067772490389322e-03 * daysPerYear, - vy: 1.62824170038242295e-03 * daysPerYear, - vz: -9.51592254519715870e-05 * daysPerYear, - mass: 5.15138902046611451e-05 * solarMass, - } - sun = Body{ - mass: solarMass, - } -) - -func main() { - flag.Parse() - - system := NewSystem([]Body{sun, jupiter, saturn, uranus, neptune}) - fmt.Printf("%.9f\n", system.energy()) - for i := 0; i < *n; i++ { - system.advance(0.01) - } - fmt.Printf("%.9f\n", system.energy()) -} |