bug in dsolve in Maple V.5 (20.4.98)

Dr Francis J. Wright

There appears to be a new bug in Release 5 that prevents Maple from solving odes with conditions if the unknown function is an indexed name rather than a symbol.

Release 4 could do this. I think that the problem is in the library procedure `dsolve/IC/format`. The worksheet


proposes a fix and gives a test example, although I have not investigated this very deeply nor tested it very thoroughly. I would be interested to hear of examples where my fix also fails. The problem is essentially that this procedure tries to treat functions, e.g. y(0), and derivatives, e.g. D(y)(0), the same, in a way that happens to work if y is a symbol but not if it is indexed, e.g. z[1].

(The indexed notation z[i] is pleasanter than the symbol notation z.i when dealing with a system of odes.)

Edgardo S. Cheb-Terrab (26.6.98)

Yes, it was in `dsolve/IC/format`. This problem was detected in January, and posted in sci.math.symbolic. A fix to this is also provided inside the ODEtools package available at http://lie.uwaterloo.ca/odetools.html.