Hi before I reinvent the wheel, has anyone coded up the Lerch Phi function? [ The Lerch Phi function is defined as phi(a,s,b) = \sum_{k=1}^\infty\frac{a^k}{(b+k)^s} ] -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743