The ev approach should work fine assuming that expr is an expression
involving i and j:
rior(expr,sizee) := genmatrix(lambda([i,j],ev(expr)),size,size)
On Fri, Dec 23, 2011 at 11:34, Erich Neuwirth
<erich.neuwirth at univie.ac.at>wrote:
> Let me explain a littel bit more:
> I want to use genmatrix ith a lambda expression.
> something like
>
> rior(expr,sizee) := genmatrix(lambda([i,j],expr),size,size)
>
> and then do
>
> rior(a[i],3)
>
> Any suggestions for doing this in an elegant way
> (I know how to do this nicely in Mathematica, but I want to use
> maxima to make it accessible to my students)
>
>
>
> On 12/23/2011 5:18 PM, Stavros Macrakis wrote:
> > ev(x) where x is a symbol seems to be OK. I'd be more comfortable if we
> > had a simple eval function that did only that, though. Of course, any
> > time you use an eval function you have to be careful about things like
> > scope.
> >
> > -s
> >
> > On Fri, Dec 23, 2011 at 11:06, Raymond Toy <toy.raymond at gmail.com
> > <mailto:toy.raymond at gmail.com>> wrote:
> >
> > On 12/23/11 7:07 AM, Stavros Macrakis wrote:
> >> subst(expr,'expr,lambda([i],expr))
> >> buildq([expr],lambda([i],expr))
> >>
> >> Both return lambda([i],i).
> >>
> >> Examples of use:
> >>
> >> expr: '(i^2)$
> >> myfun: subst(expr,'expr,lambda([i],expr))$
> >> myfun(5) => 25
> >>
> >> or simply
> >>
> >> lambda([i],ev(expr))(5) => 25
> >>
> > Is this one of the cases where ev is the right thing to use?
> >
> > Ray
> >
> >
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