Re: function definition difficulty
- To: mathgroup at smc.vnet.net
- Subject: [mg56988] Re: function definition difficulty
- From: dh <dh at metrohm.ch>
- Date: Thu, 12 May 2005 02:32:21 -0400 (EDT)
- References: <d5s9ee$ljp$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi Marc, I think you fooled yourself, your example is correct and working: cdtable = {{1.941,1.149, 0.911, 0.725, 0.678, 0.74}, {2.094, 1.098, 0.911, 0.516, 0.305,0.18}}; cd[x_] := cdtable[[If[x < 1000., 1, 2], i]]; i = 3; cd[999] returns 0.911 P.O. It would help if you put a bit more effort into your writing. sincerely, Daniel Marc No=EBl wrote: > I have a function say :sz[x_]:= cc (x/1000)^cd + cfcc, cd and cf are coefficients to be chosen in a list say forcd:cdtable = {{1.941,1.149, 0.911, 0.725, 0.678, 0.74}, {2.094, 1.098, 0.911, 0.516, 0.305, 0.18}}Here is where it gest tricky :I want to chose the nth part of either the first or the second sublistof cdtable depending on the value of x (the constant "i" being defined beforehand).I triedand cd[x_] := =cdtable[[If[x < 1000., 1, 2],i]]orchoice[x_]:=If[x < 1000., 1, 2]cd[x_]:= cdtable[[choice[x],i]]then if I typei=3;cd[999]I ought to get the result asOut[]= 0.911ihowever, I get Part::pspec:"Part specification If[x <1000., 1, 2] is neither an > integer nor a list of integers. Plus...can anyone provide a simple way out of this?I have a function say :sz[x_]:= cc (x/1000)^cd + cfcc, cd and cf are coefficients to be chosen in a list sayforcd:cdtable = {{1.941, 1.149, 0.911, 0.725, 0.678, 0.74}, {2.094, 1.098, 0.911, 0.516, 0.305,0.18}}Here is where it gest tricky :I want to chose the nth part of either the first or the second sublistofcdtable depending on the value of x (the constant "i" being defined beforehand).I triedand cd[x_] := cdtable[[If[x <1000., 1, 2],i]]orchoice[x_]:=If[x < 1000., 1,2]cd[x_]:= cdtable[[choice[x],i]]then if I typei=3;cd[999]Iought to get the result as Out[]= 0.911ihowever, I get Part::pspec:"Part specification If[x <1000., 1, 2] isneither an > integer nor a list of integers. Plus...can anyone provide a simple way out of this? >