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MySQL Great Circle Distance (Haversine formula)
..._rad = $distance/$R;
$distance_rad_plus = $distance_rad * 1.06; // ovality error for outer bounding box
$dist_deg_lat = rad2deg($distance_rad_plus); //outer bounding box
$dist_deg_lon = rad2deg($distance_rad_plus/cos(deg2rad($lat)));
$dist_deg_lat_small = rad2deg($distance_rad/sqrt(2)); //inner boun...
Node.js + Nginx - What now?
...omain.com;
access_log /var/log/nginx/subdomain.your_domain.access.log;
error_log /var/log/nginx/subdomain.your_domain.error.log debug;
location / {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarder-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host...
How can I ensure that a division of integers is always rounded up?
...ng practices. Research your tools, specify the desired behaviour, consider error cases first, and write the code to emphasize its obvious correctness. And when you find a bug, consider whether your algorithm is deeply flawed to begin with before you just randomly start swapping the directions of com...
Executing multi-line statements in the one-line command-line?
...rs in your source code that are not meant for the shell may cause a syntax error or alter the string unexpectedly.
Additionally, the shell's own \ processing in double-quoted strings can get in the way; for instance, to get Python to produce literal output ro\b, you must pass ro\\b to it; with a '...
Default function arguments in Rust
...tly saying they want to go with your default value, and will get a compile error if they put nothing. Think of it as typing add(DefaultValue, DefaultValue).
You could also use a macro:
fn add(a: i32, b: i32) -> i32 {
a + b
}
macro_rules! add {
($a: expr) => {
add($a, 2)
...
A migration to add unique constraint to a combination of columns
... unique: true
Trying to create two similar records will throw a database error (Postgres in my case):
ActiveRecord::RecordNotUnique: PG::UniqueViolation: ERROR: duplicate key value violates unique constraint "index_ownerships_on_user_id_and_post_id"
DETAIL: Key (user_id, post_id)=(1, 1) already...
What is the X-REQUEST-ID http header?
...de that ID in every log statement that it creates. If a client receives an error it can include the ID in a bug report, allowing the server operator to look up the corresponding log statements (without having to rely on timestamps, IPs, etc).
As this ID is generated (randomly) by the client it does...
How to determine CPU and memory consumption from inside a process?
...y (PDH), which is a bit "unintuitive" and takes a lot of painful trial and error to get to work. (At least it took me quite a while, perhaps I've been only a bit stupid...)
Note: for clarity all error checking has been omitted from the following code. Do check the return codes...!
Total Virtual...
How does collections.defaultdict work?
...
Usually, a Python dictionary throws a KeyError if you try to get an item with a key that is not currently in the dictionary. The defaultdict in contrast will simply create any items that you try to access (provided of course they do not exist yet). To create such ...
Most efficient way to create a zero filled JavaScript array?
... are medium fast for small arrays
solution based on Array.apply (P) throws error for big arrays
function P(n) {
return Array.apply(null, Array(n)).map(Number.prototype.valueOf,0);
}
try {
P(1000000);
} catch(e) {
console.error(e.message);
}
Code and example
Below code presents s...