The definition section mainly defines variables and constants, and the syntax is as follows:
DECLARE
Virablename [CONSTANT] dataType [NOT null][:=|default exp or value];
The following guidelines should be followed when naming variables or
Today, I learned a bit about computational geometry, which is about determining whether a point is within a triangle (on a two-dimensional plane). One of the algorithms is "the same direction method", mainly with the cross product to determine
Vectors are the standard tool for 2D and 3D Mathematical research, and in 3D games vectors are the basis. Therefore, it is very important to master some basic concepts and properties of vectors and common operation methods. In this blog, horse and
One, List
A list is a sequence of values enclosed in parentheses that can be any value or NULL, such as: (1, 5.3, "Hello", 2), empty list: ().Note: A list containing only one numeric value (for example: (43.2)) is different from the value itself
one. DataType (data type ):Perl's data types are roughly four: Scalar (variables), Scalar Array (array), hash array (hash), References (pointer), but they seem to be small but more than sufficient. In particular, you can write a Perl program without
This article is reproduced from others:PS: Since the SVD decomposition indefinitely, this text is translated, the original text with meticulous analysis + a large number of visual graphics to demonstrate the meaning of SVD. It is not easy to explain
The physical meaning of matrix and its transformation, eigenvalues and eigenvectorsRecently in the clustering of the use of PCA technology, which involves some of the matrix eigenvalues and eigenvectors of the content, on the Internet to find an
Peter D. Turney,Patrick PantelTranslation: South China Normal University-Wu Yunyu2. Semantic vector space modelThe statistical semantic hypothesis (statistical semantics hypothesis) is the unifying theme of the various vsms discussed in this paper:
Analyze the specific meaning of the PHPobject object. Everyone knows that PHPobject object initialization: to initialize an object, use the new statement to instance the object to a variable .? Phpclassfoo {functiondo_foo () {echoDoingfoo. ;}}$ bar
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