Re: calculate Recurrence Equations

*To*: mathgroup at smc.vnet.net*Subject*: [mg68755] Re: calculate Recurrence Equations*From*: "Mark Westwood" <markc.westwood at gmail.com>*Date*: Fri, 18 Aug 2006 03:11:59 -0400 (EDT)*References*: <ec1a1u$omo$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Frank Check the section 2.5.9 in The Mathematica Book for an explanation of this solution. Modify your second definition to read: anteil[n_] := anteil[n]=anteil[n - 1] + (anteil[n - 1]*5 - 1)/100 The effect of this is that the values of anteil[n] are stored when first calculated, and not recalculated next time they are required. You can see the effect by executing ?anteil after executing the function. On my PC anteil[30] runs in a second or so. Regards Mark Westwood Frank Hechtner wrote: > hi, > > i?m in trouble with my Recurrence Equations: > > i?ve defined the following function > > anteil[0] = 1 > anteil[n_] := anteil[n - 1] + (anteil[n - 1]*5 - 1)/100 > > i want mathematica to calculate the values for anteil[30] and so on. > > Unfortunately mathematica needs for this calculation over 2 hours (and > is still running, athlon x2 4600, 2 gb ram). > > I don?t see where are the difficulties for mathematica... > > Thanx for your help > > frank