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leaningtech
Attempting to cd into files works, and breaks current working directory display
Calling cd with a file argument (rather than a directory) works, which is unexpected. It also seems to break the current working directory display if you try to cd out of it afterwards:
user@:~/examples/nodejs$ cd nbody.js
user@:~/examples/nodejs/nbody.js$ ls
ls: cannot open directory '.': Not a directory
user@:~/examples/nodejs/nbody.js$ cd ../
user@:~/examples/nodejs/nbody.js/../$ ls
environment.js nbody.js primes.js test.js wasm.js
user@:~/examples/nodejs/nbody.js/../$
Thanks for the report. I can reproduce the bug, it will be fixed in the next build
There's something else weird that happens.
user@:/$ mkdir nbody.js/a
user@:/$ ls
bin boot bootstrap dev etc home lib lib64 libx32 lost+found media mnt nbody.js opt proc root run sbin srv sys tmp usr var
user@:/$ ls /nbody.js
/nbody.js
user@:/$ ls /nbody.js/
/nbody.js/
user@:/$ ls /nbody.js/a
user@:/$ cd /nbody.js
user@:/nbody.js$ ls
ls: cannot open directory '.': Not a directory
user@:/nbody.js$ cd a
user@:/nbody.js/a$ ls
user@:/nbody.js/a$ ls ..
..
user@:/nbody.js/a$ cd ..
user@:/nbody.js/a/..$ cd a
user@:/nbody.js/a/../a$ cd /
user@:/$ cat /nbody.js/a
.-a@
..e14e2681bbbb9c1757d9b74f436a6fd 38392 contrib/binary-arm64/Packages.xz
cda0212ef552426f6e79866179436c95 123 contrib/binary-arm64/Release
775b940b63e21dcf1201e4185772e93e 162641 contrib/binary-armel/Packages
49b563646c07fd93eaf0d4034ce0ea00 44488 contrib/binary-armel/Packages.gz
bc758ba23a621569ff729531a5132e9b 37632 contrib/binary-armel/Packages.xz
78cc72efdace9c58267768f953bfe4f2 123 contrib/binary-armel/Release
9cc6d6e6aadaaa2d97ddb08bc277e38a 174740 contrib/binary-armhf/Packages
5bf63d6b072432479a2b7dbf3e993d6b 47626 contrib/binary-armhf/Packages.gz
9df70088856b9332e694ab42c79f08f8 40100 contrib/binary-armhf/Packages.xz
b25c8d08b24f66bb452ef10b823c1630 123 contrib/binary-armhf/Release
ee45fcb697ff253c93a53f19a0bb3c41 206346 contrib/binary-i386/Packages
dc3e5cb607d96da9241379a6debda3da 55258 contrib/binary-i386/Packages.gz
e84a2b2a1c0408ef33a7187fe73ea5bb 46020 contrib/binary-i386/Packages.xz
1a110c9140b883fd5437389718880c10 122 contrib/binary-i386/Release
4dc94a162ba986659be09c8effcc5d5e 167152 contrib/binary-mips/Packages
efe2134d5eec6a86eebb6e14fce75955 45921 contrib/binary-mips/Packages.gz
09c3cb9dd750e560e9552c8458351d7c 38528 contrib/binary-mips/Packages.xz
7c6ecf4357b36258d88ba81aa07bef3b 122 contrib/binary-mips/Release
fb1f8191c669ac29015fd66cfa2f68bf 166385 contrib/binary-mips64el/Packages
72b9cdd06f29f3de5b0a2b0898d07a83 45087 contrib/binary-mips64el/Packages.gz
4c3169a6a949bfc40883e83fa9357a3d 38176 contrib/binary-mips64el/Packages.xz
c4f5a4f8425fa055834f5473227106dd 126 contrib/binary-mips64el/Release
c67dd653992d3319584438e38e45295a 167480 contrib/binary-mipsel/Packages
24395b00cfab1454c83a85bdfcd2d986 46024 contrib/binary-mipsel/Packages.gz
8b9bd532e0ce2b910a5dd0884bb7f129 38532 contrib/binary-mipsel/Packages.xz
23b07e19bbcf29da5ff092d8c8e110d7 124 contrib/binary-mipsel/Release
1fd40764221f0d7b292a1848b56d01d5 168973 contrib/binary-ppc64el/Packages
1084f8b33f96ae843edeb611670a0683 46071 contrib/binary-ppc64el/Packages.gz
ceb29a78e7e8f126f70c881ae6c97b01 38804 contrib/binary-ppc64el/Packages.xz
d1d756a9e620a004e1d518d1bd949314 125 contrib/binary-ppc64el/Release
84fe89c3386cf1bf0e7cbdfe9e34ddb6 164862 contrib/binary-s390x/Packages
3c964fd530c7b6bba9427f2d7bff23c2 45121 contrib/binary-s390x/Packages.gz
41abd32e21e3bffff165088c4ad92081 37952 contrib/binary-s390x/Packages.xz
0d9c11bcd0636be33ecfe0e293c9ecf1 123 contrib/binary-s390x/Release
d41d8cd98f00b204e9800998ecf8427e 0 contrib/debian-installer/binary-all/Packages
4a4dd3598707603b3f76a2378a4504aa 20 contrib/debian-installer/binary-all/Packages.gz
8dc5aea5b03dff8595f096f9e368e888 32 contrib/debian-installer/binary-all/Packages.xz
3540e0dfdd07e4a08106c31722a2a1fc 121 contrib/debian-installer/binary-all/Release
d41d8cd98f00b204e9800998ecf8427e 0 contrib/debian-installer/binary-amd64/Packages
4a4dd3598707603b3f76a2378a4504aa 20 contrib/debian-installer/binary-amd64/Packages.gz
8dc5aea5b03dff8595f096f9e368e888 32 contrib/debian-installer/binary-amd64/Packages.xz
92ffe460657a67a91558fd2f7ab79764 123 contrib/debian-installer/binary-amd64/Release
d41d8cd98f00b204e9800998ecf8427e 0 contrib/debian-installer/binary-arm64/Packages
4a4dd3598707603b3f76a2378a4504aa 20 contrib/debian-installer/binary-arm64/Packages.gz
8dc5aea5b03dff8595f096f9e368e888 32 contrib/debian-installer/binary-arm64/Packages.xz
cda0212ef552426f6e79866179436c95 123 contrib/debian-installer/binary-arm64/Release
d41d8cd98f00b204e9800998ecf8427e 0 contrib/debian-installer/binary-armel/Packages
4a4dd3598707603b3f76a2378a4504aa 20 contrib/debian-installer/binary-armel/Packages.gz
8dc5aea5b03dff8595f096f9e368e888 32 contrib/debian-installer/binary-armel/Packages.xz
78cc72efdace9c58267768f953bfe4f2 123 contrib/debian-installer/binary-armel/Release
d41d8cd98f00b204e9800998ecf8427e 0 contrib/debian-installer/binary-user@:/$
user@:/$ cat /nbody.js
co|t PI = Math.PI;
const SOLAR_MASS = 4 * PI * PI;
const DAYS_PER_YEAR = 365.24;
function Body(x, y, z, vx, vy, vz, mass
ahisr this.y = y;
this.z = z;
this.vx = vx;
this.vy = vy;
this.vz = vz;
this.mass = mass;
}
function Jupiter() {
return new Body(
4.84143144246472090e+00,
-1.16032004402742839e+00,
-1.03622044471123109e-01,
1.66007664274403694e-03 * DAYS_PER_YEAR,
7.69901118419740425e-03 * DAYS_PER_YEAR,
-6.90460016972063023e-05 * DAYS_PER_YEAR,
9.54791938424326609e-04 * SOLAR_MASS
);
}
function Saturn() {
return new Body(
8.34336671824457987e+00,
4.12479856412430479e+00,
-4.03523417114321381e-01,
-2.76742510726862411e-03 * DAYS_PER_YEAR,
4.99852801234917238e-03 * DAYS_PER_YEAR,
2.30417297573763929e-05 * DAYS_PER_YEAR,
2.85885980666130812e-04 * SOLAR_MASS
);
}
function Uranus() {
return new Body(
1.28943695621391310e+01,
-1.51111514016986312e+01,
-2.23307578892655734e-01,
2.96460137564761618e-03 * DAYS_PER_YEAR,
2.37847173959480950e-03 * DAYS_PER_YEAR,
-2.96589568540237556e-05 * DAYS_PER_YEAR,
4.36624404335156298e-05 * SOLAR_MASS
);
}
function Neptune() {
return new Body(
1.53796971148509165e+01,
-2.59193146099879641e+01,
1.79258772950371181e-01,
2.68067772490389322e-03 * DAYS_PER_YEAR,
1.62824170038242295e-03 * DAYS_PER_YEAR,
-9.51592254519715870e-05 * DAYS_PER_YEAR,
5.15138902046611451e-05 * SOLAR_MASS
);
}
function Sun() {
return new Body(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, SOLAR_MASS);
}
const bodies = Array(Sun(), Jupiter(), Saturn(), Uranus(), Neptune());
function offsetMomentum() {
let px = 0;
let py = 0;
let pz = 0;
const size = bodies.length;
for (let i = 0; i < size; i++) {
const body = bodies[i];
const mass = body.mass;
px += body.vx * mass;
py += body.vy * mass;
pz += body.vz * mass;
}
const body = bodies[0];
body.vx = -px / SOLAR_MASS;
body.vy = -py / SOLAR_MASS;
body.vz = -pz / SOLAR_MASS;
}
function advance(dt) {
const size = bodies.length;
for (let i = 0; i < size; i++) {
const bodyi = bodies[i];
let vxi = bodyi.vx;
let vyi = bodyi.vy;
let vzi = bodyi.vz;
for (let j = i + 1; j < size; j++) {
const bodyj = bodies[j];
const dx = bodyi.x - bodyj.x;
const dy = bodyi.y - bodyj.y;
const dz = bodyi.z - bodyj.z;
const d2 = dx * dx + dy * dy + dz * dz;
const mag = dt / (d2 * Math.sqrt(d2));
const massj = bodyj.mass;
vxi -= dx * massj * mag;
vyi -= dy * massj * mag;
vzi -= dz * massj * mag;
const massi = bodyi.mass;
bodyj.vx += dx * massi * mag;
bodyj.vy += dy * massi * mag;
bodyj.vz += dz * massi * mag;
}
bodyi.vx = vxi;
bodyi.vy = vyi;
bodyi.vz = vzi;
}
for (let i = 0; i < size; i++) {
const body = bodies[i];
body.x += dt * body.vx;
body.y += dt * body.vy;
body.z += dt * body.vz;
}
}
function energy() {
let e = 0;
const size = bodies.length;
for (let i = 0; i < size; i++) {
const bodyi = bodies[i];
e += 0.5 * bodyi.mass * ( bodyi.vx * bodyi.vx + bodyi.vy * bodyi.vy + bodyi.vz * bodyi.vz );
for (let j = i + 1; j < size; j++) {
const bodyj = bodies[j];
const dx = bodyi.x - bodyj.x;
const dy = bodyi.y - bodyj.y;
const dz = bodyi.z - bodyj.z;
const distance = Math.sqrt(dx * dx + dy * dy + dz * dz);
e -= (bodyi.mass * bodyj.mass) / distance;
}
}
return e;
}
const n = +50000000;
offsetMomentum();
console.log(energy().toFixed(9));
const start = Date.now();
for (let i = 0; i < n; i++) {
advance(0.01);
}
const end = Date.now();
console.log(energy().toFixed(9));
console.log("elapsed:",end-start);
user@:/$
