Series is taking too long

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Series is taking too long*From*: Roque Donizete de Oliveira <oliveria at engin.umich.edu>*Date*: Fri, 22 Jan 93 03:15:27 -0500

There must be something wrong with Series. It took about 3 seconds to evaluate the first example below but it never evaluated the second example (I killed it after 10 minutes). I duplicated the problem many times. I was the only one using the machine (no background jobs either). ulam% math Mathematica 2.1 for DEC RISC Copyright 1988-92 Wolfram Research, Inc. -- Terminal graphics initialized -- In[1]:= Series[D[(Pi^(1/2)*(-z^2)^(1/2)*Erf[(-z^2)^(1/2)])/(E^z^2*z),z],{z,0,7}] Series[D[(Pi^(1/2)*(-z^2)^(1/2)*Erf[(-z^2)^(1/2)])/(E^z^2*z),z],{z,0,7}] 4 6 2 8 z 16 z 8 Out[1]= -2 + 4 z - ---- + ----- + O[z] 3 15 In[2]:= Series[D[(Pi^(1/2)*(-z^2)^(1/2)*Erf[(-z^2)^(1/2)])/(E^z^2*z),z],{z,0,9}] Series[D[(Pi^(1/2)*(-z^2)^(1/2)*Erf[(-z^2)^(1/2)])/(E^z^2*z),z],{z,0,9}] Thanks for any help. Roque oliveria at engin.umich.edu