OpenEuphoria

RE: matheval update

• Posted by Al Getz <Xaxo at aol.com> Jun 22, 2003
• 458 views

Matt Lewis wrote:
> 
> 
> --- Al Getz <Xaxo at aol.com> wrote:
> 
> > Hello again Matt,
> > 
> > What is your basic method of handling algebraic equations?
> > 
> > like:
> > 
> >     y=x*2*(z+9)
> 
> Sorry it's taken so long...been on vacation, and have had phone
> troubles...anyway...
> 
> I'm not sure what you're asking, exactly.  I don't have a copy of 
> matheval
> handy right now, but the value of 'Y' would be set to something like
> (pseudo-matheval):
> 
> MULTIPLY( 2x, ADD(z, 9))
> 
> You could do this by parsing and evaluating "y:=x*2*(z+9)" or by parsing
> "x*2*(z+9)" and passing that to SetVar().  To evaluate y at specific 
> points
> (x,z), just use SetVar() to set the values of x and z, then Evaluate() 
> y:
> 
> sequence void, y
> void = Evaluate( Parse( "y:=x*2*(z+9)" ))
> y = Parse( "y" )
> for i = 1 to 3 do
>   for j = 1 to 3 do
>     SetVar( "x", i )
>     SetVar( "z", j )
>     printf(1,"y(%d, %d) = %s\n", {i, j, PPExp( Evaluate( y ) ) })
>   end for
> end for
> 
> The symbolic stuff all happens in symeval.e.  I have routines like 
> MultiplyOut,
> SeparateAddition, LikeTerms, etc, which are somewhat self explanatory, 
> and move
> stuff around so that they can be simplified.
> 
> Matt Lewis
> 
> 
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Hello again Matt,

Ok thanks, i'll have to take a look at it soon.

Take care for now,
Al