Brief question: faster to zero before direct computation?

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Miguel 2014-12-18

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关闭： Miguel 2014-12-18

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Hello all, quick question,

in the simplest of examples,

x1a = linspace(-1,1,100);
y1a = zeros(1,100);
y1a = x1a.^3;

Is it a clear computational speed and economy advantage to declare y1a first with zeros, or not, in this simple case?

Is the cube operation one that does not require nor benefit from variable declaration?

Cheers

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per isakson 2014-12-18

编辑：per isakson 2014-12-18

Not just confusing. It was wrong; a "no" was missing. I've edited the comment.

Miguel 2014-12-18

Ok then, I reckon this answers it, I would like to know, however, if the statement y1a = x1a.^3 is something that builds the y1a variable one by one increasing its size after each value is computed, or, what I am suspecting is the case, applies the operation first to the x1a matrix, and then assigns this to variable y1a?

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