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How to write log base(2) in c/c++

... #define M_LOG2E 1.44269504088896340736 // log2(e) inline long double log2(const long double x){ return log(x) * M_LOG2E; } (multiplication may be faster than division) ...
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What's the difference between lists and tuples?

...e pairs of page and line number to reference locations in a book, e.g.: my_location = (42, 11) # page number, line number You can then use this as a key in a dictionary to store notes on locations. A list on the other hand could be used to store multiple locations. Naturally one might want to ad...
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Task not serializable: java.io.NotSerializableException when calling function outside closure only o

...t 2013 presentation. As a side note, you can rewrite rddList.map(someFunc(_)) to rddList.map(someFunc), they are exactly the same. Usually, the second is preferred as it's less verbose and cleaner to read. EDIT (2015-03-15): SPARK-5307 introduced SerializationDebugger and Spark 1.3.0 is the first ...
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Python Image Library fails with message “decoder JPEG not available” - PIL

...you are on 64bit or 32bit Ubuntu. For Ubuntu x64: sudo ln -s /usr/lib/x86_64-linux-gnu/libjpeg.so /usr/lib sudo ln -s /usr/lib/x86_64-linux-gnu/libfreetype.so /usr/lib sudo ln -s /usr/lib/x86_64-linux-gnu/libz.so /usr/lib Or for Ubuntu 32bit: sudo ln -s /usr/lib/i386-linux-gnu/libjpeg.so /usr/l...
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Why is there no xrange function in Python3?

...tion has nothing to do with it. (Not surprising, as a one-time call to the __iter__ slot isn't likely to be visible among 10000000 calls to whatever happens in the loop, but someone brought it up as a possibility.) But it's only 30% slower. How did the OP get 2x as slow? Well, if I repeat the same ...
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“Incorrect string value” when trying to insert UTF-8 into MySQL via JDBC?

...y 4 bytes in UTF-8. You may also have to set the server property character_set_server to utf8mb4 in the MySQL configuration file. It seems that Connector/J defaults to 3-byte Unicode otherwise: For example, to use 4-byte UTF-8 character sets with Connector/J, configure the MySQL server with cha...
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sbt-assembly: deduplication found error

...le assemblyMergeStrategy in assembly := { case PathList("META-INF", xs @ _*) => MergeStrategy.discard case x => MergeStrategy.first } This helped me a lot. share | improve this answer ...
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How to check for null in Twig?

... Notice: as Twig 2.x check for variable is equal to value like is_ sameas must be {% if var is same as(false) %} not {% if var is sameas(false) %} see Doc url => twig.symfony.com/doc/2.x/tests/sameas.html – ahmed hamdy Jul 15 '19 at 17:01 ...
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What is a C++ delegate?

...ouble d)> f = std::bind(&MyClass::DoStuff, this, std::placeholders::_1); // auto f = std::bind(...); in C++11 Option 7: templates Accept anything as long as it matches the argument list. template <class FunctionT> int DoSomething(FunctionT func) { return func(3.14); } ...
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How do you turn a Mongoose document into a plain object?

...the result of doc.toObject(). http://mongoosejs.com/docs/api.html#document_Document-toObject share | improve this answer | follow | ...