Multiple plots: oddities (bugs?), missing features in Xmaxima and wxMaxima

On 09/16/2011 04:49 PM, Virgil L wrote:
> Thanks, Mario:
> It does seem that draw2d addresses the issues mentioned before. I had 
> focused on plot2d since it seems to have a simpler interface, but 
> draw2d seems manageable.

Package draw has been written with complex scenes in mind, and to avoid 
users to consult the Gnuplot manual every time they need special plots. 
Probably, most of the time, users only need to plot simple curves and 
surfaces; in that cases, plot?d commands are more simple to type than in 
draw?d.

> It seems as though draw2d interface may perhaps be cosmetically 
> simplified... for example, it seems that the declaration 
> explicit/implicit could be made optional -- if it is not already so -- 
> since the absence/presence of an equal sign , =, provides the same 
> information (if I understand correctly). So that  for example[ 
> x^3,x,-1,1] can be unambiguously inferred to mean explicit(x^3,x,-1,1) 
> whereas [y^2=x^3-2*x+1, x, -4,4, y, -4,4] could 
> be unambiguously inferred to mean implicit(y^2=x^3-2*x+1, x, -4,4, y, 
> -4,4) because of the equal sign.

The implicit example is equivalent to

implicit(-y^2+x^3-2*x+1, x, -4,4, y, -4,4)

When the equal symbol is not present, Maxima assumes that the expression 
is equal to zero. This is a convention also used in other parts of Maxima.

I know some people don't like to write 'explicit' and would prefer the 
use of square brackets, following the plot?d rules. On the contrary, I 
think there must be a general norm for all graphic objects, which makes 
easier to read and understand complex plots.

There are some solutions:

1.- When a user wants an specific syntax, he can write a wrapper, a 
simple Maxima function, to call draw commands. There are some 
user-written packages following this way.

2.- Instead of writing 'explicit', 'implicit', or even worse, 
'parametric_surface', We could define 'e', 'i', or 'ps', as 
abbreviations inside package draw. This is not difficult to implement.


> On a related note, I also find matlab's convention to indicate line 
> specs extremely handy, especially in "multiplot" (hold) interactive 
> mode... For example, 'r:' means red dotted line, and 'b--' means blue 
> dash line, 'k-.' means black dash dot, etc. A command using this looks 
> like: plot(t,sin(t),'-.r').
> See http://www.mathworks.de/help/techdoc/ref/linespec.html

GOTO 1;

> Thanks again.

Thank you for your comments and interest.

>
> Virgil

--
Mario