rounding to zero small numbers (NOT round function)
62 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
hey
so i want matlab to consider every number below a certain level (for example 0.001) as zero in the whole script. while right now it returns some computation result even in 10e-15, is there any defult value for matlab ?
0 commentaires
Réponses (1)
dpb
le 30 Oct 2019
No. ML basic numeric type is the floating point double which around zero has roughly the above magnitude of precision.
You'll have to set values less than your chosen threshold to zero explicitly.
The round function with the optional second option could be useful tool in this, but simply
x(x<threshold)=0;
will avoid the rounding that occurs in it. Of course, you'll want to use abs to get both positive and negative sides of the rounding that will likely occur.
You might also find ismembertol of use depending upon your actual code.
9 commentaires
Walter Roberson
le 31 Oct 2019
I would be interested to see what shows up for
dets = det(sym(B))
detn = double(dets)
However for large B this can take a fair while.
You might want to look at https://cseweb.ucsd.edu/classes/wi15/cse252B-a/nullspace.pdf at how null space can be determined by SVD. That form would give you the flexibility to permit columns that you consider "close enough" to zero.
Voir également
Catégories
En savoir plus sur Linear Algebra dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!