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Circle line-segment collision detection algorithm?
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(x - h)2 + (y - k)2 = r2
(h,k) = center of circle.
Note: We've simplified the problem to 2D here, the solution we get applies also in 3D
to get:
Expand
x2 - 2xh + h2 + y2 - 2yk + k2 - r2 = 0
Plug
x = ex + tdx
y = ey + tdy
( ex + tdx )2 - 2( ex + tdx )h + h2 +
( ey + tdy )2 - 2( ey + tdy ...
What's the best way to send a signal to all members of a process group?
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You don't say if the tree you want to kill is a single process group. (This is often the case if the tree is the result of forking from a server start or a shell command line.) You can discover process groups using GNU ps as follows:
p...
How do I create a unique ID in Java? [duplicate]
...eMillis;
private long discriminator;
public IdFactoryImpl() throws UnknownHostException {
this.hostName = InetAddress.getLocalHost().getHostAddress();
this.creationTimeMillis = System.currentTimeMillis();
this.lastTimeMillis = creationTimeMillis;
}
public synchronized Serializa...
Filtering for empty or NULL names in a queryset
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You could do this:
Name.objects.exclude(alias__isnull=True)
If you need to exclude null values and empty strings, the preferred way to do so is to chain together the conditions like so:
Name.objects.exclude(alias__isnull=True).exclude(alias__exact='')
Chaining these methods togethe...
What is “the inverse side of the association” in a bidirectional JPA OneToMany/ManyToOne association
...nship will not be bidirectional (the inverse aka "many" side will have no knowledge of its "owner"). This can be desirable for encapsulation/loose coupling:
// "One" Customer owns the associated orders by storing them in a customer_orders join table
public class Customer {
@OneToMany(cascade = ...
os.path.dirname(__file__) returns empty
...lename into components without taking into account the current directory. If you want to also consider the current directory, you have to do so explicitly.
To get the dirname of the absolute path, use
os.path.dirname(os.path.abspath(__file__))
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`Apache` `localhost/~username/` not working
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Thanks, it solved mine too, I'd be glad to know why it didn't work with Require local and the + signs!
– Sassan
Oct 5 '15 at 2:12
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Allowed characters in filename [closed]
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To be more precise about Mac OS X (now called MacOS) / in the Finder is interpreted to : in the Unix file system.
This was done for backward compatibility when Apple moved from Classic Mac OS.
It is legitimate to use a / in a file name in the Finder, looki...
Android: Clear the back stack
...ol to FB for login from a page with nohistory as true, the FB app does not now where to land after loging the user in, in my case it was returning to the phone home screen and I almost lost my job!
– Skynet
Mar 13 '15 at 7:18
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What is the most accurate way to retrieve a user's correct IP address in PHP?
...VER variables headers available for IP address retrieval. I was wondering if there is a general consensus as to how to most accurately retrieve a user's real IP address (well knowing no method is perfect) using said variables?
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