How to set -0.0000 and 0.0000 as zero in matlab?

21 Ansichten (letzte 30 Tage)
Haya Ali
Haya Ali am 17 Mär. 2023
Bearbeitet: Stephen23 am 17 Mär. 2023
By a long calculation I get this array
A1 =
Columns 1 through 13
-0.0000 0.2825 -0.0000 -0.4251 0.0000 1.8665 -0.0000 -0.4917 -0.0000 -1.2564 -3.0573 0.0000 0.9482
Columns 14 through 24
-0.0000 -0.0000 -0.1321 1.8201 -1.2423 -0.0000 0.5664 -0.0000 0.0816 -0.6590 -0.0000
I want to change each element that is greater than zero as 1, smaller than zero as -1 and zero remains zero but matlab is cosnidering 0.0000 and -0.0000 as 1 too. Like this
Z = -(A1<0) + (A1>0)
Z =
Columns 1 through 21
-1 1 -1 -1 1 1 -1 -1 -1 -1 -1 1 1 -1 -1 -1 1 -1 -1 1 -1
Columns 22 through 24
1 -1 -1
Is there a way to keep zeros as zeros? Please help

Akzeptierte Antwort

Stephen23
Stephen23 am 17 Mär. 2023
Bearbeitet: Stephen23 am 17 Mär. 2023
"Is there a way to keep zeros as zeros? "
Zeros are zeros.
But the data you show are not zero: the trailing digits tell us that those values are not zero. Compare:
V = [0,eps(0),pi,-pi] % zero and not-zero and +pi and -pi
V = 1×4
0 0.0000 3.1416 -3.1416
Is the 1st value zero? Yes (note no trailing digits).
Is the 2nd value zero? No (the trailing digits tell us this).
So the answer is very clear, that you need to take into account that those values are not zero.
For example, use a tolerance:
tol = 1e-5;
Z = (V>tol)-(V<-tol)
Z = 1×4
0 0 1 -1
or use ROUND beforehand:
W = round(V,5) % look, those are *exactly* zero!
W = 1×4
0 0 3.1416 -3.1416
Z = (W>0)-(W<0)
Z = 1×4
0 0 1 -1

Weitere Antworten (0)

Kategorien

Mehr zu Get Started with MATLAB finden Sie in Help Center und File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by