@OliverB Something like this?

Adding to your prior code,

ff := proc(x, y)
  local res;
  if not [x, y]::list(numeric) then
    return 'procname'(_passed);
  end if;
  res := f(x, y);
  if not res::numeric then -1000; else res; end if;
end proc;

vlo, vhi := 100, 900;
ContPlotimpl := plots:-display(
  seq(plots:-implicitplot(ff(x, y) = v, x = -200 .. 200, y = -200 .. 200,
                          color = ColorTools:-Color("HSV", [0.667*(1 - (v - vlo)/(vhi - vlo)), 1, 1]),
                          legend = v), v = vlo .. vhi, 50));

plots:-display(ContPlotimpl, Tubeout, Tubein, Coreout);

ps. Workbooks are awkward to use here (and I find them awkward altogether). If possible, I'd much prefer to get a .mw file. (Thanks)

@ControlLaw Is there some special reason that you cannot show us your actual expression?

@OliverB Having the actual data would be useful.

@OliverB Yes, in Maple 2021 the contourplot command does not itself have any direct options for providing a rainbow of colors (eg. via colorscheme).

It could still be done by programmatically manipulating the resulting structure returned by your version's contourplot command. That's not terribly difficult, but I'm afraid that I don't have time to write that today.

One alternative might be to simply call implicitplot for each color and contour value pair that you want, and plots:-display the results together.

Another alternative might be to call densityplot instead of implicitplot (with a piecewise? that is undefined out of bounds, perhaps, or disabled extrapolation?, or a bounding hull?), with the desired color effect.

What do you mean by this?

   log/(x__3^(1/2)*x__4)

Are you trying to call the log command on something?

What do you mean by,

   F5 := 1/sqrt(x__3) = -2*log(2.51)/(F3*sqrt(x__3));

if you've already assigned an equation to F3, ie.

   F3 := 0.1*p*x__4/u = 0.1*p*x__4/u;

It doesn't make sense if you're making things with a form like,

   F5  :=  blah = blech*( foo = bar )

since that's an equation with another equation on its right-hand side. That's not just a problem for Maple; it doesn't make much sense mathematically.

I changed your Post into a Question.

In future, please submit your queries as Questions, rather than as Posts. Thank you.

Another alternative here is to use PolyhedralSets. That too produces a lightweight plot with cleanly rendered boundaires, but with less need for thinking about the inequalities and region.

We could optionally remove the sphere symbols at the vertices, adjust the view, etc.

Download polyhedral_ex.mw

@C_R You wrote about five inequalities (now adjusted). But four inequalities are sufficient, and are given by the OP. Ie,

   0<=x, x<=y, y<=z, z<=1

Please don't start wholly separate new Question threads for this problem.

@Christopher2222 What is the size of your actual Matrix?

If it's datatype=float[8] then is ImageTools:-Threshold fast enough?

Or is it so large (and not just floats), so that you really need parallelism?

Did you read the Help page for that command?

If so, then which specific parts of did you not understand?

Could you provide your complete example?

@OliverB It's always a good idea to inform us up front if you're using an older version, thanks. I've now adjusted the Product field of this Question.

In Maple 2021 the contourplot command didn't recognize an appliable module (as returned by Interpolate, say) as something it could accept for its operator form calling sequence.

You could try either of these, instead,

plots:-contourplot((x,y)->f(x,y),
                   min(data[..,1])..max(data[..,1]),
                   min(data[..,2])..max(data[..,2]),
                   contours=[seq(100 .. 1000, 100)]);

plots:-contourplot(f(x,y),
                   x=min(data[..,1])..max(data[..,1]),
                   y=min(data[..,2])..max(data[..,2]),
                   contours=[seq(100 .. 1000, 100)]);

interp_cont_data_2021.mw

If that still doesn't work then please upload and attach either as .mw file, or a zip-file of the .maple workbook. Your .maple file attachment is not accessible (a problem of this site, I think).

@MaPal93 The idea was that you could use the instance that contains the placeholder names. You could apply coeff to that.

collect_complete_ac_coeffissue_ac.mw

(friendly ps. I'm reminded of this old jest.)

If you have followup queries for this problem then please add that here instead of spawning wholly separate new Question threads.