MaplePrimes Questions

hi. We are currently stuck to use the looping function to find the next value using previous value. The expected result as shown in the maple file. Can anyone assist us?

m := [80, 79, 83, 92, 74, 80, 87, 77, 103, 84, 87, 77, 88, 86, 83, 80, 79, 80, 93, 68, 106, 76, 103]

[80, 79, 83, 92, 74, 80, 87, 77, 103, 84, 87, 77, 88, 86, 83, 80, 79, 80, 93, 68, 106, 76, 103]





" for i  from 3 to  23  by 2  do   f[i+1] :=(2)/(3)*m[i+1]+(2)/(3)*m[i]-(1)/(3)*m[i-1];   f[i]=f[i+1];     f[i+2]:=(2)/(11)n[i-1]-(9)/(11)n[i]+(12)/(11)f[i]+(6)/(11)m[i+2];       "

expected result

n=3,f4=2/3m[4] + 2/3m[3]-1/3m[2]




n=5, f[6]=2/3m[6]+2/3f[5]-1/3f[4]








in V 2023 on windows, I can get server.exe to crash each time on this call. Do others see the same problem? I have not tried this on V 2022 to see if this new bug or not.

make sure to save ALL your work before trying this. I found Maple itself hangs also after the server.exe crash, so might not be able to save any work you have in your worksheets that are open at the time. 

I do not know if there is a workaround this. Does the program need to check for something to make sure it will not crash Maple before using this function? try/catch does not help with this. So now my program simply crash each time when it reads this problem.




Attached worksheet.



`Standard Worksheet Interface, Maple 2023.0, Windows 10, March 6 2023 Build ID 1689885`








 Does anyone know why my code is not running?

I am using this command: plotsetup(png, plotoutput = "titleofmylistofplots", plotoptions = "width=1920,height=1080")

in the execution block right before a sequence of split execution blocks, each made of plots:-display( seq( plot( [$ 20], series1of8[1..20,j], color=cols1[j]), j=1..3)); (I have 8 series: series1of8, series2of8, series3of8 and so on...)

When I open the output .png file, it only contains the last plot, that is the plot of series8of8. I want my file to contain all 8 plots. How to change the plotsetup() command accordingly?

My program simply keeps hanging.

It takes me 5 days to complete something which should take 2-3 hrs, since Maple keeps hanging, and I have to keep terminating server.exe and start again. Sometimes when I start again it does not hang where it was. I do this dozens of time per day.

even though I use timelimit on every possible Maple call. The problem also is that when timelimit works, it takes 10-20 times more time than asked. I ask for 10 second timeout, sometimes it timesout after 3-10 minutes if I am lucky.

So I keep trying to make workarounds and I am tired of all of this. Just waste of time. This is getting worst with each new Maple release not better.

Here is an example


    print("time used ",time[real]()-t0,"seconds");
    print("timed out");
end try;

in Maple 2023, with 128 GB RAM and very fast PC and nothing else is running, it hangs. I could leave it for hrs, the server.exe  is running at full CPU and timelimit is ignored. Timelimit in Maple is useless.

I do not know what else to do. if someone can suggest something, I am willing to try anything before I finally give up.


Hi everyone, I am seeking help regarding the graphs for analytic and numeric solutions and their errors separately?

I Have drawn a contour graph for my problem. I am looking for help on how to change the colours between every two lines according to desire. Or how can I use different colours like rainbow etc?

I am looking for help regrading change of colours between contours lines, means if there is 10 countour lines, then the gap between two line have different colour then other. Atleast repeat  colours scheme after 7 colours like rainbow combination.....As e reference please check this picture

For the function coulditbe it says

The environment variable _EnvTry can be used to specify the intensity of the testing by the is and coulditbe routines. Currently _EnvTry can be set to normal (the default) or hard. If _EnvTry is set to hard, is and coulditbe calls can take exponential time.

But how does one know the current value of _EnvTry which is supposed to be set to normal.? If I do   _EnvTry it does not show any value.  And when I do 


I do not see _EnvTry even listed.  I wanted to make sure I am setting it correctly.

Is it enough to do this?


  #now use coulditbe, it should use hard value?
end proc;


Would the above actually tell coulditbe to try hard? I wanted to use this inside a proc without affecting any global setting it might have. It is not possible to tell by just calling it if it actually using the hard option or not.

I do not think I am setting this right, I just tried

  #now use coulditbe, it should use hard value?
end proc;

And it did not complain or anything. Any value I put seems to work. I must be not setting this correctly as coulditbe does not complain.

I wish help would give example usages. But Maple help is not good at all as it has no usage examples to help users.

btw, I think the use of environment variables is bad in programming.

Each function should instead accept options as argument and one should set an option explictly.  So coulditbe should have an explicit optional argument to pass it. This makes the code more clear when looking at the call also.

Programming environment variables are just like global variables.

Bad way to program as in large program one can lose track of these settings.


I have implemented FDM for  nonlinear coupled equation 

I that I have to plot U versus Y=i*h and C versus Y 

As well Theta(T) versus Y 

And I want to calculate U(0.5) T(0.5) and C(0.5)

For different values of M 

Like M=1,2,3

Please give me command for the plot and table value of U ,T,&C (0.5)

# Parameter values:
 Pr:=1:E:=1:A:=0.1:Sc:=0.01: K:=0.5:

a := 0: b := 1: N := 9:
h := (b-a)/(N+1): k := (b-a)/(N+1):

 lambda:= 1/h^2:  lambda1:= 1/k^2:
# Initial conditions
for i from 0 to N do
  U[i, 0] := h*i+1:
end do:

for i from 0 to N do
  T[i, 0] := h*i+1:
end do:
for i from 0 to N do
  C[i, 0] := h*i+1:
end do:

# Boundary conditions
for j from 0 to N+1 do
  U[0, j] := exp(A*j*lambda);
  U[N+1, j] := 0;
  T[0, j] := j*lambda1;
  T[N+1, j] := 0;
  C[0, j] := j*lambda1;
  C[N+1, j] := 0
end do:

#Discretization Scheme
for i to N do
  for j from 0 to N do
    eq1[i, j]:= lambda1*(U[i, j+1]-U[i, j]) = (Gr/2)*(T[i, j+1]+T[i,j])+(Gr/2)*(C[i, j+1]+C[i,j])+(lambda^2/2)*(U[i-1,j+1]-2*U[i,j+1]+U[i+1,j+1]+U[i-1,j]-2*U[i,j]+U[i+1,j])-(M/2)*(U[i,j+1]+U[i,j]) ;
    eq2[i, j]:= lambda1*(T[i, j+1]-T[i, j]) = (1/Pr)*(lambda^2/2)*(T[i,j+1]-2*T[i,j+1]+T[i+1,j+1]+T[i-1,j]-2*T[i,j]+T[i+1,j])+(E*lambda^2)*((U[i+1,j]-U[i,j])^2);
    eq3[i, j]:= lambda1*(C[i, j+1]-C[i, j]) = (1/Sc)*(lambda^2/2)*(C[i,j+1]-2*C[i,j+1]+C[i+1,j+1]+C[i-1,j]-2*C[i,j]+C[i+1,j])+(K/2)*((C[i,j+1]+C[i,j]))  
  end do
end do:

  `union`(  seq(seq( indets( eq1[i,j], name), i=1..N), j=0..N),
            seq(seq( indets( eq2[i,j], name), i=1..N), j=0..N),
            seq(seq( indets( eq3[i,j], name), i=1..N), j=0..N)



{Gr, M, C[1, 1], C[1, 2], C[1, 3], C[1, 4], C[1, 5], C[1, 6], C[1, 7], C[1, 8], C[1, 9], C[1, 10], C[2, 1], C[2, 2], C[2, 3], C[2, 4], C[2, 5], C[2, 6], C[2, 7], C[2, 8], C[2, 9], C[2, 10], C[3, 1], C[3, 2], C[3, 3], C[3, 4], C[3, 5], C[3, 6], C[3, 7], C[3, 8], C[3, 9], C[3, 10], C[4, 1], C[4, 2], C[4, 3], C[4, 4], C[4, 5], C[4, 6], C[4, 7], C[4, 8], C[4, 9], C[4, 10], C[5, 1], C[5, 2], C[5, 3], C[5, 4], C[5, 5], C[5, 6], C[5, 7], C[5, 8], C[5, 9], C[5, 10], C[6, 1], C[6, 2], C[6, 3], C[6, 4], C[6, 5], C[6, 6], C[6, 7], C[6, 8], C[6, 9], C[6, 10], C[7, 1], C[7, 2], C[7, 3], C[7, 4], C[7, 5], C[7, 6], C[7, 7], C[7, 8], C[7, 9], C[7, 10], C[8, 1], C[8, 2], C[8, 3], C[8, 4], C[8, 5], C[8, 6], C[8, 7], C[8, 8], C[8, 9], C[8, 10], C[9, 1], C[9, 2], C[9, 3], C[9, 4], C[9, 5], C[9, 6], C[9, 7], C[9, 8], C[9, 9], C[9, 10], T[1, 1], T[1, 2], T[1, 3], T[1, 4], T[1, 5], T[1, 6], T[1, 7], T[1, 8], T[1, 9], T[1, 10], T[2, 1], T[2, 2], T[2, 3], T[2, 4], T[2, 5], T[2, 6], T[2, 7], T[2, 8], T[2, 9], T[2, 10], T[3, 1], T[3, 2], T[3, 3], T[3, 4], T[3, 5], T[3, 6], T[3, 7], T[3, 8], T[3, 9], T[3, 10], T[4, 1], T[4, 2], T[4, 3], T[4, 4], T[4, 5], T[4, 6], T[4, 7], T[4, 8], T[4, 9], T[4, 10], T[5, 1], T[5, 2], T[5, 3], T[5, 4], T[5, 5], T[5, 6], T[5, 7], T[5, 8], T[5, 9], T[5, 10], T[6, 1], T[6, 2], T[6, 3], T[6, 4], T[6, 5], T[6, 6], T[6, 7], T[6, 8], T[6, 9], T[6, 10], T[7, 1], T[7, 2], T[7, 3], T[7, 4], T[7, 5], T[7, 6], T[7, 7], T[7, 8], T[7, 9], T[7, 10], T[8, 1], T[8, 2], T[8, 3], T[8, 4], T[8, 5], T[8, 6], T[8, 7], T[8, 8], T[8, 9], T[8, 10], T[9, 1], T[9, 2], T[9, 3], T[9, 4], T[9, 5], T[9, 6], T[9, 7], T[9, 8], T[9, 9], T[9, 10], U[1, 1], U[1, 2], U[1, 3], U[1, 4], U[1, 5], U[1, 6], U[1, 7], U[1, 8], U[1, 9], U[1, 10], U[2, 1], U[2, 2], U[2, 3], U[2, 4], U[2, 5], U[2, 6], U[2, 7], U[2, 8], U[2, 9], U[2, 10], U[3, 1], U[3, 2], U[3, 3], U[3, 4], U[3, 5], U[3, 6], U[3, 7], U[3, 8], U[3, 9], U[3, 10], U[4, 1], U[4, 2], U[4, 3], U[4, 4], U[4, 5], U[4, 6], U[4, 7], U[4, 8], U[4, 9], U[4, 10], U[5, 1], U[5, 2], U[5, 3], U[5, 4], U[5, 5], U[5, 6], U[5, 7], U[5, 8], U[5, 9], U[5, 10], U[6, 1], U[6, 2], U[6, 3], U[6, 4], U[6, 5], U[6, 6], U[6, 7], U[6, 8], U[6, 9], U[6, 10], U[7, 1], U[7, 2], U[7, 3], U[7, 4], U[7, 5], U[7, 6], U[7, 7], U[7, 8], U[7, 9], U[7, 10], U[8, 1], U[8, 2], U[8, 3], U[8, 4], U[8, 5], U[8, 6], U[8, 7], U[8, 8], U[8, 9], U[8, 10], U[9, 1], U[9, 2], U[9, 3], U[9, 4], U[9, 5], U[9, 6], U[9, 7], U[9, 8], U[9, 9], U[9, 10]}




  fsolve( eval( [ seq(seq(eq1[i,j], i=1..N),j=0..N),
                  seq(seq(eq2[i,j], i=1..N),j=0..N),
                  seq(seq(eq3[i,j], i=1..N),j=0..N)
                [Gr=1.0, M=2]

plot(eval([seq([i*h, U])],thickness = 4, axes = boxed, labels = [U, y], color = red, title = "FDM"));



I have FORTRAN namelist files, that have the form like






In these files there are no blank lines as automatically put in above,

The goal is to read such files into Maple and have the same varNames created in Maple to be names/symbols with the values shown in the FORTRAN file assigned to those Maple names. In other words, Maple should then have

varName1 := 0.600:

varName2 := 123:

varName3 := 345.0:

This would enable the Maple to use these variables in the usual way to make calculations, etc.

I know how to read the FORTRAN files and get the varNames and values into two separate Maple tables, but I haven't found a way to then make the Maple assignments that are required. There must be a way to accomplish the goal.

Thank you for any suggestions.

      --- Mike

Hi everyone, Could anyone help me to draw horizontal and vertical line in a plot? Also, How to add command for legends to show inside the plot at empty space. I every time edit legends in paint manually. For reference, I am attaching a picture


I do not know if this is known issue. In V 2023  I was calling odetest on solution to ode. It gives the above internal exception.

This happens when there is signum's in the solution and shows up when kernelopts('assertlevel'=2): is set.

Code is below. Could someone verify if they see this or not and if this looks like a new bug? If so, will send email to support.

When I replaced all the signum(...) calls by 1, the exception went away. I do not know now if this happens in V 2022 or not. 

The problem with these internal exception is that they can not be cought. So the whole program crash even when using try/catch.

ode:=3*x^2+9*y(x)*x+5*y(x)^2-(6*x^2+4*y(x)*x)*diff(y(x),x) = 0;

current_sol_for_y:=x = -1805/9*(x^2+y(x)*x+1/3*y(x)^2)^2*(7/8*((x+10/7*y(x))*abs(x)+10/21*signum(x)*y(x)^2)*signum(3*x+2*y(x))*signum(21*x^2+30*y(x)*x+10*y(x)^2)+x^2+5/4*y(x)*x+5/12*y(x)^2)^2*(x^2+25/19*y(x)*x+25/57*y(x)^2)^2*c[1]/(11/9*(21/44*abs(x)^3+y(x)*(x+15/22*y(x))*abs(x)+5/33*signum(x)*y(x)^3)*signum(3*x+2*y(x))*signum(21*x^2+30*y(x)*x+10*y(x)^2)+(x^2+5/4*y(x)*x+5/12*y(x)^2)*(x+2/3*y(x)))^2/x^4/(x+2/3*y(x))^2;




`Standard Worksheet Interface, Maple 2023.0, Windows 10, March 6 2023 Build ID 1689885`





ode:=3*x^2+9*y(x)*x+5*y(x)^2-(6*x^2+4*y(x)*x)*diff(y(x),x) = 0;

3*x^2+9*y(x)*x+5*y(x)^2-(6*x^2+4*y(x)*x)*(diff(y(x), x)) = 0

current_sol_for_y:=x = -1805/9*(x^2+y(x)*x+1/3*y(x)^2)^2*(7/8*((x+10/7*y(x))*abs(x)+10/21*signum(x)*y(x)^2)*signum(3*x+2*y(x))*signum(21*x^2+30*y(x)*x+10*y(x)^2)+x^2+5/4*y(x)*x+5/12*y(x)^2)^2*(x^2+25/19*y(x)*x+25/57*y(x)^2)^2*c[1]/(11/9*(21/44*abs(x)^3+y(x)*(x+15/22*y(x))*abs(x)+5/33*signum(x)*y(x)^3)*signum(3*x+2*y(x))*signum(21*x^2+30*y(x)*x+10*y(x)^2)+(x^2+5/4*y(x)*x+5/12*y(x)^2)*(x+2/3*y(x)))^2/x^4/(x+2/3*y(x))^2:


Error, (in Algebraic:-MakeMonic) assertion failed in assignment to p, expected algfun, got (312500*signum(x)^2*_X000001+625000*signum(x)*_X000001+312500*_X000001)*_Z^12+(3750000*x*signum(x)^2*_X000001+9375000*x*signum(x)*_X000001+1875000*abs(x)*signum(x)*_X000001+5625000*x*_X000001+1875000*abs(x)*_X000001)*_Z^11+(20175000*x^2*signum(x)^2*_X000001+64350000*x^2*signum(x)*_X000001+23812500*x*abs(x)*signum(x)*_X000001+46987500*x^2*_X000001+29437500*x*abs(x)*_X000001+2812500*abs(x)^2*_X000001)*_Z^10+(63450000*x^3*signum(x)^2*_X000001+265950000*x^3*signum(x)*_X000001+136800000*x^2*abs(x)*signum(x)*_X000001+240750000*x^3*_X000001+212737500*x^2*abs(x)*_X000001+37687500*x*abs(x)^2*_X000001)*_Z^9+(6400*x^5*signum(x)^2+127399500*x^4*signum(x)^2*_X000001+19200*x^5*signum(x)+732339000*x^4*signum(x)*_X000001+465435000*x^3*abs(x)*signum(x)*_X000001+14400*x^5+842314500*x^4*_X000001+932985000*x^3*abs(x)*_X000001+230203125*x^2*abs(x)^2*_X000001)*_Z^8+(19200*x^6*signum(x)^2+167022000*x^5*signum(x)^2*_X000001+144000*x^6*signum(x)+57600*x^5*abs(x)*signum(x)+1403001000*x^5*signum(x)*_X000001+1030887000*x^4*abs(x)*signum(x)*_X000001+172800*x^6+86400*x^5*abs(x)+2119149000*x^5*_X000001+2755512000*x^4*abs(x)*_X000001+841792500*x^3*abs(x)^2*_X000001)*_Z^7+(14400*x^7*signum(x)^2+139455000*x^6*signum(x)^2*_X000001+434880*x^7*signum(x)+257280*x^6*abs(x)*signum(x)+1892559600*x^6*signum(x)*_X000001+1537209900*x^5*abs(x)*signum(x)*_X000001+911520*x^7+774720*x^6*abs(x)+3929588100*x^6*_X000001+129600*x^5*abs(x)^2+5746914900*x^5*abs(x)*_X000001+2035037250*x^4*abs(x)^2*_X000001)*_Z^6+(67716000*x^7*signum(x)^2*_X000001+660960*x^8*signum(x)+383040*x^7*abs(x)*signum(x)+1773867600*x^7*signum(x)*_X000001+1538222400*x^6*abs(x)*signum(x)*_X000001+40320*x^5*abs(x)^3*signum(x)+2760480*x^8+2907360*x^7*abs(x)+5409374400*x^7*_X000001+768960*x^6*abs(x)^2+8623980900*x^6*abs(x)*_X000001+60480*x^5*abs(x)^3+3388246200*x^5*abs(x)^2*_X000001)*_Z^5+(14620500*x^8*signum(x)^2*_X000001+505440*x^9*signum(x)+190080*x^8*abs(x)*signum(x)+1104921000*x^8*signum(x)*_X000001+992007000*x^7*abs(x)*signum(x)*_X000001+120960*x^6*abs(x)^3*signum(x)+5249124*x^9+5844528*x^8*abs(x)+5484333420*x^8*_X000001+1710864*x^7*abs(x)^2+9295977960*x^7*abs(x)*_X000001+453600*x^6*abs(x)^3+3921403995*x^6*abs(x)^2*_X000001+181440*x^5*abs(x)^4)*_Z^4+(155520*x^10*signum(x)+412759800*x^9*signum(x)*_X000001+372130200*x^8*abs(x)*signum(x)*_X000001+90720*x^7*abs(x)^3*signum(x)+6417144*x^10+6636816*x^9*abs(x)+3992402520*x^9*_X000001+1691712*x^8*abs(x)^2+7039884960*x^8*abs(x)*_X000001+1369872*x^7*abs(x)^3+3103144020*x^7*abs(x)^2*_X000001+810432*x^6*abs(x)^4)*_Z^3+(70178400*x^10*signum(x)*_X000001+61406100*x^9*abs(x)*signum(x)*_X000001+4925124*x^11+4035744*x^10*abs(x)+1980134100*x^10*_X000001+627264*x^9*abs(x)^2+3558613500*x^9*abs(x)*_X000001+2082024*x^8*abs(x)^3+1599802650*x^8*abs(x)^2*_X000001+1206576*x^7*abs(x)^4+63504*x^5*abs(x)^6)*_Z^2+(2169504*x^12+1026432*x^11*abs(x)+600579360*x^11*_X000001+1077330780*x^10*abs(x)*_X000001+1592136*x^9*abs(x)^3+482845860*x^9*abs(x)^2*_X000001+598752*x^8*abs(x)^4+190512*x^6*abs(x)^6)*_Z+419904*x^13+84214080*x^12*_X000001+147374640*abs(x)*x^11*_X000001+489888*abs(x)^3*x^10+64476405*abs(x)^2*x^10*_X000001+142884*abs(x)^6*x^7



Hi,  I went through QuizBuilder (a new feature in Maple 2023) using pre-programmed templates to customize my code. My issue lies in the connection of my random variable F in the 'show solution' to provide the correct limit. Thank you for your insights.,

Write a Maple procedure called "matricediag" which takes as input a square matrix M of m rows and m columns and which returns The smallest element below the main diagonal and its position.

When I look for petrov type II vacuum solutions in the Metric search, one of the metrics i get is Stephani [33,8,3].

But when I load the metric and calculate the Ricci or the Einstein tensor, they are not identically zero.
Am I using the metric search wrong or is there a glitch in the program?


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