N-body problem: Difference between revisions

Content added Content deleted
(Added Algol 68)
Line 1,289: Line 1,289:
Body 2 : 0.426346 -0.111425 -0.681150 | 0.234987 0.006241 -0.440245
Body 2 : 0.426346 -0.111425 -0.681150 | 0.234987 0.006241 -0.440245
Body 3 : -1.006089 -4.103186 -3.122591 | -0.359686 -1.177995 -0.875924</pre>
Body 3 : -1.006089 -4.103186 -3.122591 | -0.359686 -1.177995 -0.875924</pre>


=={{header|COBOL}}==
{{trans|Locomotive Basic}}
<syntaxhighlight lang="cobol">

identification division.
program-id. nbody.
environment division.
configuration section.
source-computer.
System76
with debugging mode
.
repository.
function all intrinsic.
input-output section.
file-control.
select input-file assign to "nbody-file"
line sequential.
data division.
file section.
fd input-file.
01 input-record pic x(31).
01 input-rec-constant.
05 i-r-gravconstant pic 9.9999.
05 filler pic x.
05 i-r-bodies pic 9(03).
05 filler pic x.
05 i-r-timesteps pic 9(03).
05 filler pic x(17).
01 input-rec-mass.
05 i-r-mass pic 9.9999.
05 filler pic x(25).
01 input-rec-pos.
05 i-r-posx pic -9.9999.
05 filler pic x.
05 i-r-posy pic -9.9999.
05 filler pic x.
05 i-r-posz pic -9.9999.
05 filler pic x(08).
01 input-rec-vol.
05 i-r-volx pic -9.9999.
05 filler pic x(01).
05 i-r-voly pic -9.9999.
05 filler pic x(01).
05 i-r-volz pic -9.9999.
05 filler pic x(08).


working-storage section.
77 bodies pic 9(3).
77 timesteps pic 9(3).
77 gravconstant pic 9v999999.
77 i pic 999.
77 idis pic 9.
77 j pic 999.
77 t pic 999.
77 tdis pic z9.
77 c pic 999.
77 dx pic s9(9)v9(20).
77 dy pic s9(9)v9(20).
77 dz pic s9(9)v9(20).
77 distance pic s9(9)v9(20).
77 force pic s9(9)v9(20).
77 temp-vx pic s9(9)v9(20).
77 temp-vy pic s9(9)v9(20).
77 temp-vz pic s9(9)v9(20).

01 masses.
05 mass occurs 10 times pic 9v9999.
01 positions.
05 posn occurs 10 times.
10 x pic s9(9)v9(20).
10 y pic s9(9)v9(20).
10 z pic s9(9)v9(20).
10 xx pic s9v9(06).
10 yy pic s9v9(06).
10 zz pic s9v9(06).
01 velocities.
05 velocity occurs 10 times.
10 vx pic s9(9)v9(20).
10 vy pic s9(9)v9(20).
10 vz pic s9(9)v9(20).
10 vxx pic s9v9(06).
10 vyy pic s9v9(06).
10 vzz pic s9v9(06).
01 accelerations.
05 acceleration occurs 10 times.
10 ax pic s9(9)v9(20).
10 ay pic s9(9)v9(20).
10 az pic s9(9)v9(20).

procedure division.
main-procedure.
open input input-file
read input-file into input-rec-constant
move i-r-gravconstant to gravconstant
move i-r-bodies to bodies
move i-r-timesteps to timesteps

perform initiate-system
perform simulate

close input-file
stop run
.

initiate-system.
perform varying i from 1 by 1 until i > bodies
read input-file into input-rec-mass
move i-r-mass to mass(i)
read input-file into input-rec-pos
move i-r-posx to x(i)
move i-r-posy to y(i)
move i-r-posz to z(i)
read input-file into input-rec-vol
move i-r-volx to vx(i)
move i-r-voly to vy(i)
move i-r-volz to vz(i)
end-perform
.

simulate.
perform display-topline
perform varying t from 1 by 1 until t > timesteps
perform compute-accelerations
perform compute-positions
perform compute-velocities
perform resolve-collisions
perform round-results
perform display-results
end-perform
.

compute-accelerations.
perform varying i from 1 by 1 until i > bodies
move 0 to ax(i) ay(i) az(i)
perform varying j from 1 by 1 until j > bodies
if i not equal to j
compute dx rounded = x(j) - x(i)
compute dy rounded = y(j) - y(i)
compute dz rounded = z(j) - z(i)
compute distance rounded =
sqrt(dx * dx + dy * dy + dz * dz)
compute force rounded = gravconstant * mass(j)
/ (distance * distance * distance)
compute ax(i) rounded = ax(i) + force * dx
compute ay(i) rounded = ay(i) + force * dy
compute az(i) rounded = az(i) + force * dz
end-if
end-perform
end-perform
.

compute-velocities.
perform varying i from 1 by 1 until i > bodies
compute vx(i) = vx(i) + ax(i)
compute vy(i) = vy(i) + ay(i)
compute vz(i) = vz(i) + az(i)
end-perform
.

compute-positions.
perform varying i from 1 by 1 until i > bodies
compute x(i) = x(i) + vx(i) + 0.5 * ax(i)
compute y(i) = y(i) + vy(i) + 0.5 * ay(i)
compute z(i) = z(i) + vz(i) + 0.5 * az(i)
end-perform
.

resolve-collisions.
perform varying i from 1 by 1 until i > bodies - 1
perform varying j from 1 by 1 until j > bodies
if x(i) = x(j) and y(i) = y(j) and z(i) = z(j)
move vx(i) to temp-vx
move vy(i) to temp-vy
move vz(i) to temp-vz
move vx(j) to vx(i)
move vy(j) to vy(i)
move vz(j) to vz(i)
move temp-vx to vx(j)
move temp-vy to vy(j)
move temp-vz to vz(j)
end-if
end-perform
end-perform
.

round-results.
perform varying i from 1 by 1 until i > bodies
compute xx(i) rounded = x(i)
compute yy(i) rounded = y(i)
compute zz(i) rounded = z(i)
compute vxx(i) rounded = vx(i)
compute vyy(i) rounded = vy(i)
compute vzz(i) rounded = vz(i)
end-perform
.

display-topline.
display "Body : X Y Z |"
" VX VY VZ "
.

display-results.
move t to tdis
display "Cycle " tdis
perform varying i from 1 by 1 until i > bodies
move i to idis
display "Body " idis " : " xx(i) " " yy(i) " "
zz(i) " | " vxx(i) " " vyy(i) " " vzz(i)
end-perform
display " "
.
</syntaxhighlight>

Input file is nbody-file:
0.0100 003 020
1.0000
+0.0000 +0.0000 +0.0000
+0.0100 +0.0000 +0.0000
0.1000
+1.0000 +1.0000 +0.0000
+0.0000 +0.0000 +0.0200
0.0010
+0.0000 +1.0000 +1.0000
+0.0100 -0.0100 -0.0100


Test:
<syntaxhighlight lang="bash">
Compile and Test
C:\GnuCOBOL> cobc -x -O2 nbody.cbl


execute: ./nbody

output from sysout display:
Body : X Y Z | VX VY VZ
Cycle 1
Body 1 : +0.010177 +0.000179 +0.000002 | +0.010354 +0.000357 +0.000004
Body 2 : +0.998230 +0.998232 +0.020002 | -0.003539 -0.003536 +0.020004
Body 3 : +0.010177 +0.988232 +0.988055 | +0.010354 -0.013536 -0.013889

Cycle 2
Body 1 : +0.020709 +0.000718 +0.000011 | +0.010710 +0.000721 +0.000014
Body 2 : +0.992907 +0.992896 +0.039971 | -0.007109 -0.007138 +0.019935
Body 3 : +0.020717 +0.972888 +0.972173 | +0.010727 -0.017153 -0.017876

Cycle 3
Body 1 : +0.031600 +0.001625 +0.000034 | +0.011072 +0.001094 +0.000033
Body 2 : +0.983985 +0.983910 +0.059834 | -0.010735 -0.010835 +0.019790
Body 3 : +0.031643 +0.953868 +0.952235 | +0.011125 -0.020886 -0.021999

Cycle 4
Body 1 : +0.042858 +0.002913 +0.000081 | +0.011443 +0.001481 +0.000060
Body 2 : +0.971393 +0.971163 +0.079509 | -0.014448 -0.014659 +0.019561
Body 3 : +0.042981 +0.931039 +0.928087 | +0.011552 -0.024772 -0.026299

Cycle 5
Body 1 : +0.054492 +0.004595 +0.000160 | +0.011826 +0.001884 +0.000097
Body 2 : +0.955030 +0.954509 +0.098909 | -0.018278 -0.018649 +0.019238
Body 3 : +0.054766 +0.904225 +0.899522 | +0.012018 -0.028857 -0.030829

Cycle 6
Body 1 : +0.066517 +0.006691 +0.000281 | +0.012224 +0.002308 +0.000145
Body 2 : +0.934759 +0.933760 +0.117931 | -0.022265 -0.022849 +0.018806
Body 3 : +0.067040 +0.873197 +0.866280 | +0.012530 -0.033199 -0.035655

Cycle 7
Body 1 : +0.078950 +0.009225 +0.000456 | +0.012642 +0.002759 +0.000206
Body 2 : +0.910400 +0.908677 +0.136456 | -0.026454 -0.027316 +0.018244
Body 3 : +0.079856 +0.837662 +0.828023 | +0.013101 -0.037871 -0.040861

Cycle 8
Body 1 : +0.091815 +0.012227 +0.000702 | +0.013086 +0.003245 +0.000284
Body 2 : +0.881722 +0.878958 +0.154340 | -0.030902 -0.032122 +0.017523
Body 3 : +0.093281 +0.797239 +0.784313 | +0.013749 -0.042975 -0.046559

Cycle 9
Body 1 : +0.105140 +0.015737 +0.001035 | +0.013564 +0.003775 +0.000383
Body 2 : +0.848429 +0.844216 +0.171401 | -0.035684 -0.037362 +0.016600
Body 3 : +0.107405 +0.751427 +0.734579 | +0.014498 -0.048649 -0.052908

Cycle 10
Body 1 : +0.118964 +0.019805 +0.001481 | +0.014085 +0.004362 +0.000509
Body 2 : +0.810137 +0.803953 +0.187408 | -0.040900 -0.043166 +0.015414
Body 3 : +0.122346 +0.699554 +0.678056 | +0.015384 -0.055097 -0.060138

Cycle 11
Body 1 : +0.133337 +0.024498 +0.002071 | +0.014662 +0.005025 +0.000672
Body 2 : +0.766343 +0.757509 +0.202050 | -0.046687 -0.049720 +0.013868
Body 3 : +0.138268 +0.640690 +0.613685 | +0.016460 -0.062633 -0.068603

Cycle 12
Body 1 : +0.148327 +0.029907 +0.002851 | +0.015317 +0.005792 +0.000888
Body 2 : +0.716377 +0.703998 +0.214889 | -0.053246 -0.057302 +0.011810
Body 3 : +0.155406 +0.573482 +0.539941 | +0.017816 -0.071782 -0.078886

Cycle 13
Body 1 : +0.164025 +0.036157 +0.003887 | +0.016079 +0.006709 +0.001184
Body 2 : +0.659310 +0.642172 +0.225282 | -0.060887 -0.066351 +0.008976
Body 3 : +0.174112 +0.495836 +0.454475 | +0.019596 -0.083511 -0.092045

Cycle 14
Body 1 : +0.180564 +0.043437 +0.005286 | +0.017000 +0.007852 +0.001613
Body 2 : +0.593807 +0.570186 +0.232208 | -0.070119 -0.077621 +0.004875
Body 3 : +0.194929 +0.404136 +0.353320 | +0.022038 -0.099890 -0.110265

Cycle 15
Body 1 : +0.198150 +0.052049 +0.007234 | +0.018171 +0.009372 +0.002283
Body 2 : +0.517817 +0.485100 +0.233878 | -0.081861 -0.092550 -0.001535
Body 3 : +0.218605 +0.290860 +0.228583 | +0.025314 -0.126661 -0.139210

Cycle 16
Body 1 : +0.217126 +0.062542 +0.010117 | +0.019781 +0.011614 +0.003484
Body 2 : +0.427899 +0.381659 +0.226654 | -0.097974 -0.114332 -0.012913
Body 3 : +0.244268 +0.131956 +0.057562 | +0.026013 -0.191148 -0.202831

Cycle 17
Body 1 : +0.238346 +0.076539 +0.015221 | +0.022658 +0.016380 +0.006723
Body 2 : +0.317489 +0.248502 +0.200967 | -0.122846 -0.151982 -0.038461
Body 3 : +0.075592 -0.559591 -0.487315 | -0.363366 -1.191945 -0.886924

Cycle 18
Body 1 : +0.263123 +0.097523 +0.026918 | +0.026898 +0.025587 +0.016672
Body 2 : +0.173428 +0.050424 +0.112716 | -0.165275 -0.244174 -0.138041
Body 3 : -0.286241 -1.745597 -1.369528 | -0.360299 -1.180066 -0.877501

Cycle 19
Body 1 : +0.270854 +0.113045 +0.061923 | -0.011436 +0.005457 +0.053339
Body 2 : +0.199821 -0.093105 -0.208666 | +0.218061 -0.042882 -0.504723
Body 3 : -0.646318 -2.924909 -2.246453 | -0.359856 -1.178559 -0.876350

Cycle 20
Body 1 : +0.258572 +0.116046 +0.112038 | -0.013129 +0.000544 +0.046890
Body 2 : +0.426346 -0.111425 -0.681150 | +0.234987 +0.006241 -0.440245
Body 3 : -1.006089 -4.103186 -3.122591 | -0.359686 -1.177995 -0.875924

</syntaxhighlight>


=={{header|D}}==
=={{header|D}}==
Retrieved from "https://rosettacode.org/wiki/N-body_problem"