How do you create an array around a central value?
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I would like to write a function such as:
function [ array ] = generate_array( center_pt, resolution )
NB_POINTS = 5;
(...)
end
so that calling [ array ] = generate_array( 5, 2.5 )
array = [0 2.5 5 7.5 10]
采纳的回答
Star Strider
2015-4-6
How about this? It has three arguments, since I don’t know if you want the number of points to be an argument or decided by the function.
NrPts = 5;
CtrPt = 5;
Res = 2.5;
generate_array = @(CtrPt,NrPts,Res) linspace(CtrPt-Res*fix(NrPts/2), CtrPt+Res*fix(NrPts/2), NrPts);
It generates the array you specified, and seems to be robust for other argument values.
4 个评论
PR
2015-4-6
Star Strider
2015-4-6
My pleasure.
If you always only want 5 points, my anonymous function becomes:
generate_array = @(CtrPt,Res) linspace(CtrPt-Res*2, CtrPt+Res*2, 5);
The linspace function is about as efficient as it is possible to get, and has been a part of MATLAB as long as I can remember. You could probably do this with a loop, but a simple colon-operator vector would seem to do as well, at least in the current application, although I cannot guarantee how robust it would be for other situations:
generate_array = @(CtrPt,Res) [CtrPt-Res*2 : Res : CtrPt+Res*2];
(The square brackets aren’t strictly necessary, but it improves the readability of the code. I know by looking at it that it is an array.)
I still prefer (and recommend) to use linspace because of its flexibility.
PR
2015-4-6
Star Strider
2015-4-6
My pleasure! I very much appreciate your compliment.
In Answers, we (collectively) strive to post the most efficient and fastest code, assuming that is what the person who posts the Question wants. Most of us also provide links to the relevant documentation, as well as a brief explanation of how the code we post works, using comments on each line or a short narrative description.
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