RE : string to identifier

You can also use eval_string from the package stringproc.

Laurent.

> -----Message d'origine-----
> De?: maxima-bounces at math.utexas.edu [mailto:maxima-bounces at math.utexas.edu] De la part de
> Adam Majewski
> Envoy??: dimanche 22 janvier 2012 01:08
> ??: maxima at math.utexas.edu
> Objet?: Re: [Maxima] string to identifier
> 
> On 22.01.2012 00:07, Richard Fateman wrote:
> >
> >
> > Try
> > ?intern(concat("list",123)) :: 32
> >
> > which assigns 32 to a symbol that you can type in to Maxima as ?LIST123.
> >
> >
> > There is a peculiarity of switching upper and lower case for
> > convoluted reasons.
> >
> > Note that is "::" not ":"
> >
> > RJF
> It works now. Thanks.
> 
> Below is code in which I have used it in main and draw sections.
> It draws 5 images on the screen.
> 
> 
> Adam
> 
> ==============
> kill(all);
> 
> 
> 
> /* ---------- functions ---------------------- */
> 
> /* conformal map  from circle to cardioid ( boundary
>   of period 1 component of Mandelbrot set */
> F(w):=w/2-w*w/4;
> 
> 
> /*
> circle D={w:abs(w)=1 } where w=l(t,r)
> t is angle in turns ; 1 turn = 360 degree = 2*Pi radians
> r is a radius
> */
> ToCircle(t,r):=r*%e^(%i*t*2*%pi);
> 
> 
> 
> 
> /*
> 
> http://en.wikipedia.org/wiki/Complex_quadratic_polynomial
> */
> f(z,c):=z*z+c $
> 
> GiveCriticalOrbit(c,iMax):=
>     /*
>     computes (without escape test)
>     critical orbit (forward orbit of critical point )
>     and saves it to the list for draw package */
> block(
>   [z,orbit,temp],
>   z:0, /* first point = critical point z:0+0*%i */
>   orbit:[[realpart(z),imagpart(z)]],
>   for i:1 thru iMax step 1 do
>          ( z:expand(f(z,c)),
>            orbit:endcons([realpart(z),imagpart(z)],orbit)),
> 
>   return(orbit)
> )$
> 
> 
> /* find fixed point alfa , returns a list */
> GiveFixed(c):=
> (
>   [z],
> z:float(rectform((1-sqrt(1-4*c))/2)),
> [[realpart(z),imagpart(z)]]
> )$
> 
> 
> 
> GiveC(angle,radius):=
> (
>   [w],
>   /* point of  unit circle   w:l(internalAngle,internalRadius); */
>   w:ToCircle(angle,radius),  /* point of circle */
>   float(rectform(F(w)))    /* point on boundary of period 1 component of
> Mandelbrot set */
> )$
> 
> 
> 
> compile(all)$
> 
> 
> 
> /* ---------- constant ---------------------------*/
> Numerator :1;
> DenominatorMax :5;
> InternalRadius:1;
> iMax:500;
> 
> 
> /* -------------- main ----------------- */
> 
> 
> 
> for Denominator:1 thru DenominatorMax step 1 do
> (
>   InternalAngle: Numerator/Denominator,
>   c: GiveC(InternalAngle,InternalRadius),
>    /*  */
>   ?intern(concat("z",string(Denominator)))::GiveFixed(c),
>   /* */
>   ?intern(concat("orbit",string(Denominator)))::GiveCriticalOrbit(c,iMax)
> );
> 
> 
> 
> 
> /*------------------draw -------------------------------------*/
> load(draw); /* ( interface to gnuplot ) by Mario Rodriguez Riotorto
> http://www.telefonica.net/web2/biomates */
> 
> draw(
> 
>      terminal  = screen,
>      columns =5,
>      gr2d(
>          title= "1/1  ",
> 	user_preamble = "set border 0;set nokey;set size square;set noxtics
> ;set noytics;",
> 
>          point_type    = filled_circle,
> 	points_joined = false,
>          point_size    = 0.7,
>          /*  */
> 	color		  =red,
> 	key = "critical orbit",
> 	points(?ORBIT1),
>          /*  */
> 	color		  =black,
> 	point_size    = 1.4,
> 	key = "parabolic fixed point",
> 	points(?Z1),
>          /*  */
> 	color		  =blue,
> 	key = "criitical point",
> 	points([0],[0])
>          ),
> 
>   gr2d(
>          title= " 1/2 ",
> 	user_preamble = "set border 0;set nokey;set size square;set noxtics
> ;set noytics;",
> 
>          point_type    = filled_circle,
> 	points_joined = false,
>          point_size    = 0.7,
>          /*  */
> 	color		  =red,
> 	key = "critical orbit",
> 	points(?ORBIT2),
>          /*  */
> 	color		  =black,
> 	point_size    = 1.4,
> 	key = "parabolic fixed point",
> 	points(?Z2),
>          /*  */
> 	color		  =blue,
> 	key = "criitical point",
> 	points([0],[0])
>          ),
> 
> gr2d(
>          title= " 1/3 ",
> 	user_preamble = "set border 0;set nokey;set size square;set noxtics
> ;set noytics;;",
> 	point_type    = filled_circle,
> 	points_joined = false,
>          point_size    = 0.7,
>          /*  */
> 	color		  =red,
> 	key = "critical orbit",
> 	points(?ORBIT3),
>          /*  */
> 	color		  =black,
> 	point_size    = 1.4,
> 	key = "parabolic fixed point",
> 	points(?Z3),
>          /*  */
> 	color		  =blue,
> 	key = "criitical point",
> 	points([0],[0])
>          ),
> 
> gr2d(
>          title= " 1/4 ",
> 	user_preamble = "set border 0;set nokey;set size square;set noxtics
> ;set noytics;;",
> 	point_type    = filled_circle,
> 	points_joined = false,
>          point_size    = 0.7,
>          /*  */
> 	color		  =red,
> 	key = "critical orbit",
> 	points(?ORBIT4),
>          /*  */
> 	color		  =black,
> 	point_size    = 1.4,
> 	key = "parabolic fixed point",
> 	points(?Z4),
>          /*  */
> 	color		  =blue,
> 	key = "criitical point",
> 	points([0],[0])
>          ),
> gr2d(
>          title= " 1/5 ",
> 	user_preamble = "set border 0;set nokey;set size square;set noxtics
> ;set noytics;;",
> 	point_type    = filled_circle,
> 	points_joined = false,
>          point_size    = 0.7,
>          /*  */
> 	color		  =red,
> 	key = "critical orbit",
> 	points(?ORBIT5),
>          /*  */
> 	color		  =black,
> 	point_size    = 1.4,
> 	key = "parabolic fixed point",
> 	points(?Z5),
>          /*  */
> 	color		  =blue,
> 	key = "criitical point",
> 	points([0],[0])
>          )
> 
> 
> 
>   );
> 
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