This module offers facilities to turn off the builtin Math::Symbolic 
simplification routines and replace them with routines that just clone the 
objects. You may want to do this in cases where the simplification 
routines fail to simplify the Math::Symbolic trees and waste a lot of CPU 
time. (For example, calculating the first order Taylor polynomial of a 
moderately complex test function was sped up by 100% on my machine.)

A word of caution, however: If you turn off the simplification routines, 
some procedures may produce very, very large trees. One such procedure 
would be the consecutive application of many derivatives to a product 
without intermediate simplification. This would yield exponential growth 
of nodes. (And may, in fact, still do if you keep the simplification 
heuristics turned on because most expressions cannot be simplified 
significantly.)

WWW: http://search.cpan.org/dist/Math-SymbolicX-NoSimplification