Q  
qag [Integration1D]  qag integrator f a b return an approximation i to the
integral f over the interval (a,b) hopefully satisfying
following claim for accuracy abs(i  true_result) <= max epsabs
(epsrel*abs(i)) .

W  
workspace [Integration1D]  workspace i limit creates a workspace for the integrator i
that can handle up to limit subintervals.
