help using sparse matrix

i have a big matrix 10e3x10e3 with small values 1e-10,1e-2,to save memory and speed i need the sparse function to not only ignore the zero elements but also those very small elements in the range (1e-10,1e-2) is it possible?

Answer 1

[the cyclist]

You could preprocess your matrix with a step like

M(abs(M)<1.e-2) = 0;

and then make it sparse.

Answer 2

[Kobi]

i don't get it the resault is not as i expected:

>> a=[1,2,3;4,5e-12,0;9,8,7]

a =

    1.0000    2.0000    3.0000
    4.0000    0.0000         0
    9.0000    8.0000    7.0000

>> aS=sparse(a)

aS =

   (1,1)       1.0000
   (2,1)       4.0000
   (3,1)       9.0000
   (1,2)       2.0000
   (2,2)       0.0000
   (3,2)       8.0000
   (1,3)       3.0000
   (3,3)       7.0000

>> a(abs(a)<1.e-2)

ans =

   1.0e-11 *

    0.5000
         0

what is that answer? all the other constants from the matrix disappeared

[Jos (10584)]

The expression " a(abs(a)<1.e-2) " selects those elements from a that have an absolute value smaller than 1e-2. You do not want to select them, but set those elements to a zero

a(abs(a)<1e-2) = 0

[Jos (10584)]

… and only after that convert those a to sparse!