Vectors and Sum operation

Question

bondpen 2018-3-19

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/389217-vectors-and-sum-operation

评论： bondpen 2018-3-19

采纳的回答： John D'Errico

在 MATLAB Online 中打开

Trying to use sum to figure about resistor formula, 1/[(1/r1)+1rn)] where n can be any number.

What i have come up with:

function R = scirpt(y)
         R = 1/sum(1/(y));
end

Well be entering this:

scirpt([100,200,300]) should output 54.5455

if true
  % code
end

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Answer 1

John D'Errico 2018-3-19

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/389217-vectors-and-sum-operation#answer_310704

编辑：John D'Errico 2018-3-19

在 MATLAB Online 中打开

R = 1/sum(1./y);

y is a vector. You want to divide EACH of the elements of y into 1. So you use the ./ operator, which is designed to solve element-wise operations. (Just like the .* and .^ operators.)

The other divide is a scalar/scalar operation, so / works fine there, although ./ would also be acceptable. That is:

R = 1./sum(1./y);

would also work.

Finally, there was no need to put a parens around y in your original line. So while it is fine to add additional parens if you are not sure you need them in some spot, too many parens that need not be there will only make things confusing, hard to read and debug.