3. The method of claim 1 , wherein the sketching matrix has a form of r×n, where r<<n.
3. The method of claim 1 , wherein the sketching matrix has a form of r×n, where r<<n. 4. The method of claim 3 , wherein the number of iterations required until the sketching matrix used by a linear sketch can be identified is a function of n that can be represented as first degree polynomial.