Re: Set::setraw error
- To: mathgroup at smc.vnet.net
- Subject: [mg90357] Re: Set::setraw error
- From: dh <dh at metrohm.ch>
- Date: Mon, 7 Jul 2008 05:06:27 -0400 (EDT)
- References: <g4q9kl$e6o$1@smc.vnet.net>
Hi Steven,
consider the statement: {a,b,r,s,x,y}={b,c,x-q*r,y-q*s,r,s}]; If we call
xgcd[1,2],"a" is a parameter is replaced by one, giving:
{1,2,r,s,x,y}=....;. As you can not assigne to 1 or 2 you get the error.
The same is true for all statement where you assigne to function parameters.
hope this helps, Daniel
Steven Siew wrote:
> I have encountered this Set:setraw error for the code below.
>
> I'm stumped. Does anyone have any idea what went wrong?
>
> xgcd[a_,b_]:=Module[{xsign=1,ysign=1,x=1,y=0,r=0,s=1,c,q},
> If[a == 0 && b == 0,Return[{0,0,1}]];
> If[a == 0,Return[{Abs[b],0,b/Abs[b]}] ];
> If[b == 0,Return[{Abs[a],a/Abs[a],0}]];
> If[a<0,a=-a; xsign=-1];
> If[b<0,b=-b; ysign=-1];
> While[b\[NotEqual]0,
> {c,q}={Mod[a,b],Quotient[a,b]};
> {a,b,r,s,x,y}={b,c,x-q*r,y-q*s,r,s}
> ];
> Return[{a,x*xsign,y*ysign}]
> ]
>
> xgcd[2, 3]
>
> \!\(\*
> RowBox[{\(Set::"setraw"\), \(\(:\)\(\ \)\), "\<\"Cannot assign to
> raw \
> object \\!\\(2\\). \\!\\(\\*ButtonBox[\\\"More\[Ellipsis]\\\", \
> ButtonStyle->\\\"RefGuideLinkText\\\", ButtonFrame->None, \
> ButtonData:>\\\"Set::setraw\\\"]\\)\"\>"}]\)
>
--
Daniel Huber
Metrohm Ltd.
Oberdorfstr. 68
CH-9100 Herisau
Tel. +41 71 353 8585, Fax +41 71 353 8907
E-Mail:<mailto:dh at metrohm.com>
Internet:<http://www.metrohm.com>