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How do you detect where two line segments intersect? [closed]
...bering that s × r = − r × s):
u = (q − p) × r / (r × s)
Now there are four cases:
If r × s = 0 and (q − p) × r = 0, then the two lines are collinear.
In this case, express the endpoints of the second segment (q and q + s) in terms of the equation of the first li...
How to encrypt String in Java
...t and use AES-GCM mode for all your encryptions and you shall be secure.
Now if you want to learn the nitty gritty details on how to encrypt in java read on :)
Block Ciphers
First thing first you need to pick a symmetric key Block Cipher. A Block Cipher is a computer function/program used to cr...
ERROR 1452: Cannot add or update a child row: a foreign key constraint fails
...ill need to update the data in the child table (instead of deleting them).
Now, we can utilize Left Join to find all those rows in the child table, which does not have matching values in the parent table. Following query would be helpful to fetch those non-matching rows:
SELECT child_table.*
FROM c...
Backbone.js get and set nested object attribute
...e navigation to the nested object. Basically, your callers don't need to know the model's internal structure; after all, it may change and the callers should be none the wiser.
– Bill Eisenhauer
Jun 15 '11 at 0:54
...
Naming of ID columns in database tables
... does this!)and forget to change the alias in the join condition.
So you now have
select t1.field1, t2.field2, t3.field3
from table1 t1
join table2 t2 on t1.id = t2.table1id
join table3 t3 on t1.id = t3.table2id
when you meant
select t1.field1, t2.field2, t3.field3
from table1 t1
join table...
Generate a heatmap in MatPlotLib using a scatter data set
...in plot; so do (AFAIK) all of the plotting libraries for R; still i don't know if this is the generally accepted term for plots of this type, though i suspect it's likely given that hexbin is short for hexagonal binning, which is describes the essential step in preparing the data for display.)
fr...
how do I work around log4net keeping changing publickeytoken
...
Don't know is it suitable for your particular case or not, but you can recompile one of the frameworks, so they will use log4net with the same public key. In my case it was FluentNHibernate which uses log4net 1.2.10 and Combres with...
How to get rid of `deprecated conversion from string constant to ‘char*’` warnings in GCC?
... on an exceedingly large codebase, and recently upgraded to gcc 4.3, which now triggers this warning:
24 Answers
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data.table vs dplyr: can one do something well the other can't or does poorly?
...ters. As Grace Hopper would say, Mind your nanoseconds!
3. Syntax
Let's now look at syntax. Hadley commented here:
Data tables are extremely fast but I think their concision makes it harder to learn and code that uses it is harder to read after you have written it ...
I find this remark poi...
Optimal number of threads per core
...
I know this question is rather old, but things have evolved since 2009.
There are two things to take into account now: the number of cores, and the number of threads that can run within each core.
With Intel processors, the nu...