deano -

The "standard" Solver that is included with Excel does not usually perform
well with discontinuous functions.

You may have better results if you use the Premium Solver for Education
(included with many textbooks) or other more-advanced Solvers available from
http://www.solver.com.

- Mike
http://www.mikemiddleton.com


"deano" wrote in message
ups.com...
KISS : keep It Simple Sam. This is a revised request to help on a
period solver to schedule lifts

You have a tank that contains liquid. You make liquid each day at some
rate. The tank has to hold this daily make. Tank has a max and a min
volume of liquid to hold. You have to lift liquid out of tank so that
it stays within main & max. It costs $5 + $0.42/bbl to lift liquid out.
You know how much liquid you have in tank to start and how much liquid
make for the next 21 days. what is the optimal lift schedule. See the
solver & click show scenarios available here
http://availg.com/images/stories/tools/runout_1.xls

Problem: why is solver not finding the optimal schedule of lifts
regardless of initial guess?

For Example:
go to model tab:
click show scenarios
select base then close
go to Tools solver
click solve
solve does not find optimal schedule.

click show scenarios
select optimal then close
That is the optimal solution.

Your help is greatly appreciated.