When do I need point operator when using power function?
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I want to know ,how can I know when is the point(dot) use in power,when I want to calculate something.
In matrix calculation is always need the . ?
You how to decide use or not use the point
a.^4 a^4
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Zack Peters
2013-10-26
4 个投票
The '.' syntax is used to denote element-wise multiplication. What this means is that each element of variable 'a' will be raised to the power of 4 rather than have the entire variable 'a' raised to the power of 4.
If 'a' were to be a single value then it doesn't make any difference. However, if 'a' were a matrix then you can begin to see the difference in output of the element-wise operator
~Zack
2 个评论
Mohammed Hamdalla
2022-1-26
thank you man that really helped.
As a concrete example:
A = [1 2; 3 4]
B = A.*A % Multiply each element of A by itself, element-wise
B2 = A.^2 % Same as B
C = A*A % Perform matrix multiplication
C2 = A^2 % Same as C
% Elements of C are the dot product of the corresponding rows and columns of A
C(1, 2) == dot(A(1, :), A(:, 2)) % true
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