in Matlab and Mathematica it is possible to put the labels in contour plot, directly on the lines (with nice positioning).

This makes it much much easier to see the level of each contour line since the values are on the lines,  without having to jump to the legend and guess the color and try to visually match colors with the plot.

For example, in Matlab

clear; close all;
x = 0:0.05:20;
y = 0:0.05:15;
[x,y] = meshgrid(x,y);
z = (11-x-y).^2 + (1+x+10*y-x.*y).^2;
[C,h] =contour(x,y,z,10);
clabel(C,h)

gives

In Maple

f:=(11 - x - y)^2 + (1 + x + 10*y - x*y)^2:
plots:-contourplot(f, x=0..20, y=0..15,
         legend=true,
         contours=10,
         'axes'='boxed',
         legendstyle=[location=right], 
         colorscheme="DivergeRainbow");

Is there a way to tell Maple to put contour labels on the "middle" of the level lines (contour lines) similar to what Matlab does?

I see no such option in https://www.maplesoft.com/support/help/maple/view.aspx?path=plots/contourplot

I think I remeber doing this before but not sure and it is not in my cheat sheet.

Given an expression, I wanted to find all names in it. Which can be done using indets(f,name);

But then how to check if any of the names found are not in the Maple initial known names given in https://www.maplesoft.com/support/help/Maple/view.aspx?path=initialconstants

For example,

f:=x^2 - y^2+Pi;
indets(f,name);

Gives {Pi, x, y}  how does one then check if this list does not have any known name in it?

In this case Pi. I do not want to check explicitly for each name listed on the web page above.

Are these initial known names  grouped in some specific maple type that can be used to check against?

Or is there a command in Maple to return a list of all these initially known names? If so this list can be used to check against.

Asked google AI and it did not know.

Maple 2025.2

What does Error, (in dsolve/numeric/bvp) bad index into Matrix mean?
Also, I'm trying to run it, it is slow, any suggestions?

restart;
with(Student[VectorCalculus]);
with(DynamicSystems);
with(DEtools);
with(PDEtools, ReducedForm, declare, diff_table, dsubs);
NULL;
 #Digits:= trunc(evalhf(Digits)); #generally a very efficient setting

# Here we solve a 1D problem in 3 regions. In each region, we have concentration and potential (c,phi) distributions,
# We first solve the unperturbed steady-state problem and then the linearized perturbation problem (which rely on the steady state).
# Each region is defined in x = 0..1, and the regions are connected by interface conditions that 
# connect (c1(1),phi1(1)) to (c2(0),phi2(0)) and (c2(1),phi2(1)) to (c3(0),phi3(0))

Q:=10;   omega:=100;     J0:= 0.01;   # parameters
                            Q := 10

                          omega := 100

                           J0 := 0.01

# The unperturbed steady-state

c1:=1-J0/2*x: 
c3:=1-J0/2*(x-1):  
c12:= eval(c1,x=1); 
c32 := eval(c3,x=0); 
S1:=sqrt(Q^2+4*c12^2): 
S3:=sqrt(Q^2+4*c32^2):  
c21:=eval((S1-Q)/2); 
c23:=eval((S3-Q)/2);  
I0:=fsolve(Q*i0/2/J0*ln((J0*S1-Q*i0)/(J0*S3-Q*i0))=(J0-S1+S3)/2,i0);  
V:=(I0/J0+1)*ln(c32/c12)+ln((c21+Q)/(c23+Q))+(J0+2*c23-2*c21)/Q; # the potential drop across the system 
c2:=solve(y-c21+Q*I0/2/J0*ln((Q*I0-Q*J0-2*J0*y)/(Q*I0-Q*J0-2*J0*c21))=-J0/2*x,y):  
phi1:=I0/J0*ln(c1)+V: 
phi3:=I0/J0*ln(c3): 
dphi1:=diff(phi1,x); 
dphi3:=diff(phi3,x); 
phi21:=I0/J0*ln(c12)+V-0.5*ln((c21+Q)/c21); 
phi2:=(2*c21-2*c2+Q*phi21-J0*x)/Q: 
dphi2:=diff(phi2,x); 
dphi12 := eval(dphi1, x=1); 
dphi21 := eval(dphi2, x=0); 
dphi23 := eval(dphi2, x=1); 
dphi32 := eval(dphi3, x=0); 
INT1 := int(1/(2*c1), x = 0 .. 1); 
INT2 := int(1/(2*c2 + Q), x = 0 .. 1); 
INT3 := int(1/(2*c3), x = 0 .. 1); 
INT := INT1 + INT2 + INT3;
                      c12 := 0.9950000000

                       c32 := 1.005000000

                      c21 := 0.09804129000

                      c23 := 0.1000024500

                      I0 := 0.01419804328

                       V := 0.02539628566

                              0.007099021640   
                dphi1 := - --------------------
                           1 - 0.005000000000 x

                              0.007099021640        
           dphi3 := - ------------------------------
                      1.005000000 - 0.005000000000 x

                     phi21 := -2.299074561

dphi2 := (0.001000000000 LambertW(-0.2818670588 exp(-0.2818670588

   - 0.0007043224058 x)))/(1

   + LambertW(-0.2818670588 exp(-0.2818670588 - 0.0007043224058 x)

  )) - 0.001000000000

                   dphi12 := -0.007134695118

                   dphi21 := -0.001392499832

                   dphi23 := -0.001391964358

                   dphi32 := -0.007063703124

                      INT1 := 0.5012541824

                     INT2 := 0.09805801917

                      INT3 := 0.4987541511

                       INT := 1.098066353

sys1 := {
-omega*C11(x)+diff(diff(C12(x), x), x)=0,
omega*C12(x)+diff(diff(C11(x), x), x) = 0,
-omega*C21(x)+diff(diff(C22(x), x)+(c2*sigma2-C22(x)*dphi2*Q)/(2*c2+Q), x) =0,
 omega*C22(x)+diff(diff(C21(x), x)+(c2*sigma1-C21(x)*dphi2*Q)/(2*c2+Q), x) = 0,
-omega*C31(x)+diff(diff(C32(x), x), x)=0,
omega*C32(x)+diff(diff(C31(x), x), x) = 0
}:

sys2 := {
diff(FA1(x), x) = C11(x)*dphi1/c1,
diff(FA2(x), x) = C21(x)*dphi2/(c2+Q/2),
diff(FA3(x), x) = C31(x)*dphi3/c3,
diff(FB1(x), x) = C12(x)*dphi1/c1,
diff(FB2(x), x) = C22(x)*dphi2/(c2+Q/2),
diff(FB3(x), x) = C32(x)*dphi3/c3
}: 

Bc := {
C11(0) = 0, C12(0) = 0,  C31(1) = 0, C32(1) = 0,
FA1(0) = 0, FB1(0) = 0,  FA3(1) = 0, FB3(1) = 0, 

2*C11(1)/c12 = C21(0)/(c21+Q)+C21(0)/c21, 
2*C12(1)/c12 = C22(0)/(c21+Q)+C22(0)/c21,
C21(1)/(c23+Q)+C21(1)/c23 = 2*C31(0)/c32,
C22(1)/(c23+Q)+C22(1)/c23 = 2*C32(0)/c32,

D(C11)(1)+dphi12*C11(1)-sigma1/2-c12*D(FA1)(1) = D(C21)(0)+dphi21*C21(0)-(c21+Q)*sigma1/(2*c21+Q)-(c21+Q)*D(FA2)(0),
D(C12)(1)+dphi12*C12(1)-sigma2/2-c12*D(FB1)(1) = D(C22)(0)+dphi21*C22(0)-(c21+Q)*sigma2/(2*c21+Q)-(c21+Q)*D(FB2)(0),
D(C11)(1)-dphi12*C11(1)+sigma1/2+c12*D(FA1)(1) = D(C21)(0)-dphi21*C21(0)+c21*sigma1/(2*c21+Q)+c21*D(FA2)(0),
D(C12)(1)-dphi12*C12(1)+sigma2/2+c12*D(FB1)(1) = D(C22)(0)-dphi21*C22(0)+c21*sigma2/(2*c21+Q)+c21*D(FB2)(0),

D(C31)(0)+dphi32*C31(0)-sigma1/2-c32*D(FA3)(0) = D(C21)(1)+dphi23*C21(1)-(c23+Q)*sigma1/(2*c23+Q)-(c23+Q)*D(FA2)(1),
D(C32)(0)+dphi32*C32(0)-sigma2/2-c32*D(FB3)(0) = D(C22)(1)+dphi23*C22(1)-(c23+Q)*sigma2/(2*c23+Q)-(c23+Q)*D(FB2)(1),
D(C31)(0)-dphi32*C31(0)+sigma1/2+c32*D(FA3)(0) = D(C21)(1)-dphi23*C21(1)+c23*sigma1/(2*c23+Q)+c23*D(FA2)(1),
D(C32)(0)-dphi32*C32(0)+sigma2/2+c32*D(FB3)(0) = D(C22)(1)-dphi23*C22(1)+c23*sigma2/(2*c23+Q)+c23*D(FB2)(1)
}:
 
 

all_sys := sys1 union sys2 union Bc:
sol1 := dsolve(all_sys, initmesh = 100, maxmesh = 15000, numeric, method = bvp[midrich], output = listprocedure):
#(all_sys, numeric, method = bvp[midrich]);

Error, (in dsolve/numeric/bvp) bad index into Matrix

Hello,

 I would like to bulild a Gaussian Mixture Model in Maple using the most straightforward apprach:

Apperantly something goes wrong, PDF in (5) is a product not a sum and variance is quadratic in w (6) not linear as it should be.

How to correct this?

Helllo folkx :)

What is wrong in my functions f and g ?

I don't catch the point.

Thanks.

JM--

interface(version);
    Standard Worksheet Interface, Maple 2025.2, Windows 11,
     November 11 2025 Build ID 1971053

with(RandomTools):

Generate(float(range = 2.532000 .. 7.723000, digits = 4));
                             2.537

f := x -> Generate(float(range = 0 .. 100)):

f(30);
                            94.3141

f(0.200000);
                            23.9622

randomize();
                         2413841372727

f(30);
                            86.2657

plot(f(x), x = 1 .. 100.000000);

plots[listplot](sort([seq(Generate(float(range = 0.032100 .. 162.000000, digits = 3)), i = 1 .. 20)]));

plots[listplot](sort([seq(Generate(float(range = 0.032100 .. 162.000000, digits = 3, method = uniform)), i = 1 .. 20)]));

g := ((x -> Generate(float(range = 0 .. x))) assuming (x*float and 0 < x)):

plot(g(x), x = 1 .. 50);
Error, (in RandomTools:-Generate) invalid input: unknown expects value for keyword parameter range to be of type numeric .. numeric, but received 0 .. x

Is the following behavior expected? using  t=0 .. 3*Pi  vs.  t=0 .. round(3*Pi) give different plots.  Why? Should not the plot be the same?

ps. do not know if I asked this before or not. I can't remember. Search in Mapleprimes is not easy.

Download deplot_with_round_jan_17_2026.mw

Would this be considered a bug or expected?

Everytime I see internal error in red, for me, it tells me it is a bug. But wanted to check first what others think.

Download asympt_none_real_argument_jan_17_2026.mw

I am looking for ways to clear remember tables in a Maple session to ensure that a Maple command/procedure is executed as if it were being called for the first time. I currently use

map(forget, [anames()])

but I am not sure if that statement clears all existing remeber tables (i.e. including system remember tables)?

Are there other ways to do this? Restart is not an option since it clears almost everything.

Edit: This question is not about disabling remember tables.

I'm looking for the general solution to the attached differential equation. Maple doesn't provide it. What am I doing wrong?

Download testdgl5.mw

Hi,

I am using the following (dummy) code. I would appreciate any help generating a plot with multiple functions and a legend. I am getting an error message stating that the parameter "v" is unknown. I believe the issue is due to the complexity of the functions (fun1 and fun2) that use the "piecewise" command in my code.  

fun1 := piecewise(cond1, a(x,v), cond2, b(x,v))

fun2 := piecewise(cond1, c(x,v), cond2, d(x,v))

with(plots):
myPlotFunction := proc(v)
local p1, p2:
p1 := plot(fun1, x=0..1, color = [blue], linestyle = [solid], thickness = [3], legend = ["H"]):
p2 := plot(fun2, x=0..1, color = [red], linestyle = [dash], thickness = [3], legend = ["L"]):
plots:-display({p1, p2}, title="Multiple plots");
end proc:

Explore(myPlotFunction(v), parameter={v=0..1});

Regards,

Omkar

Hello all,

This is a post for a software change.

I think it would be great if Maple had some constructions for :

i++

++i

i--

--i and idem for multiply and divide.

I guess it is too late for Maple 2026, but maybe this could be added for 2027.

i++ does work however.

Have a great day.

Jean-Michel

PS:You must have a reputation score of at least 100 to add a new tag. (???)

Sorry : I just see that this  is already implemented in Maple.

Thank you

WHen plotting f(x) and g(x) on same plot, and putting legend at bottom (default), the legends show horizontally. i.e. f(x) then g(x) on same line.

I'd like the legend to be stacked vertically, just like when the legend on the right or left, But keep it at bottom. But want to do all this in code. Not using any UI context tools or mouse.

Here is an example

Download legend_question.mw

This way back machine shows how Maple debugger looked like in the year 2005 (that is 20 years ago) in Maple 10.

And it is pretty much the same debugger today. Here is a screen shot side by side of recent version

20 YEARS and nothing changed.

The debugger in Maple is one, if not the main, selling point for Maple compared to its competitor for many.

Even the article above says this

     "But the big plus about the Maple language is that it has a debugger! "

     "Also, the existence of a reasonable debugger in Maple is a big plus. From
      personal experience, I can tell you that debugging Mathematica Notebooks
     can be both time consuming and frustrating."

Can the debugger be improved, so it is easier to use? 

All what is needed is to change the UI so  one can see more code as they are stepping in, like with Matlab debugger for example.

That is all. Currently it is a pain using the debugger, since one only sees one or 2-3  lines at time as they step in the code instead of seeing complete code with full screen which makes it much easier to see things.

Instead of Maplesoft wasting time on AI and cosmetics, do something practical for developers and improve the debugger.

It should not take a software company 40 years just to improve a UI for a debugger. What is the blocking issue here? 

Just hire one or two programmers and they can do this in 6 months.

It would be useful to have Time-Frequency signal processing tools in Maple, for non-stationary spectral analysis. One example is the Wigner-Ville Transform, along with a range of others (e.g. STFT)