epow

ith vector from canonical basis.


Syntax
   f = epow(i, n)

Description
   f = epow(i, n) returns the ith vector from the canonical basis 
   truncated at dimension n.

Inputs
   i   = vector position in the basis integer).
   n   = dimension of the truncated vector (integer).

Output
   f   = ith vector from the canonical basis (sparse vector).