round numeric 0

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Pinco
Pinco 2012-1-17
Hi everyone! I have a matrix like this:
A=[ 1 , .3*10^-8 , .2*10^-8 , .2*10^-8;
. 3*10^-8; 1; .2*10^-8;
.2*10^-8, .2*10^-8, 1];
I want 0 (real or integer) where i have a very very very small value. How can I do it?
I know I can use logical mask
A(A<10^-7=0)
but i'm looking for a matlab function that can do automatically. This is a typical numeric problem...
Thanks a lot for you answer.
Pippo

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采纳的回答

Andreas Goser
Andreas Goser 2012-1-17
This is actually done automatically if it is very very very small. But it looks the veryveryvery is different for you. The
eps
Function return what MATLAB sees as small enough to be rounded to zero.
Besides your own suggestion (probably think also of negative small values, you may use all kinds of rounding and formatting like
round
sprintf
depending on your needs.

更多回答（1 个）

Jaap
Jaap 2012-1-17
your best option:
A(A<small_value) = 0
you can also try:
A = A(bsxfun(@lt,A,1E-7))
I doubt its quicker.

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