Hello

In my last question, I asked for help converting an old Maple V3 code to the latest version. With the help of  @Rouben Rostamian, I managed to get most of the procedures working again. Unfortunately, there is one procedure that I cannot figure out how to convert. Below is the procedure, along with an example that works and one that does not.

saturbasis := proc(ps,js,ord)
 local qs,gb,zz,j,aux;
     print("ps = ",ps):
     print("js = ",js):
	 print("ord = ",ord):
     if js <> {} then
         qs := [op(ps),'`@z`.j*js[j]-1' $ ('j' = 1 .. nops(js))];print("qs = ",%):
         zz := ['`@z`.(nops(js)-j+1)' $ ('j' = 1 .. nops(js))];print("zz = ",%):
         aux:= [op(zz),'ord[nops(ord)-j+1]' $ ('j' = 1 .. nops(ord))]:print("aux = ",aux):
         gb := grobner['gbasis'](qs,aux,'plex');
         qs := [];
         for j to nops(gb) do
             if {op(zz)} minus indets(gb[j]) = {op(zz)} then
                 qs := [gb[j],op(qs)]
             fi
         od
     else qs := ps
     fi;
     qs
end proc:

First example:

ps:=[2*x1^2 + 3*x2^2 + 4*x1 + x2, x1*x3 - 3*x2 - 1, 2*x1*x4 + 3*x2 + 1]:
js:={x1}:
ord:=[x1, x2, x3, x4]:

saturbasis(ps,js,ord);
             [    2       2                                
    "ps = ", [2 x1  + 3 x2  + 4 x1 + x2, x1 x3 - 3 x2 - 1, 

                        ]
      2 x1 x4 + 3 x2 + 1]


                         "js = ", {x1}

                   "ord = ", [x1, x2, x3, x4]

             [    2       2                                
    "qs = ", [2 x1  + 3 x2  + 4 x1 + x2, x1 x3 - 3 x2 - 1, 

                                   ]
      2 x1 x4 + 3 x2 + 1, @z x1 - 1]


                         "zz = ", [@z]

                 "aux = ", [@z, x4, x3, x2, x1]

Warning, grobner[gbasis] is deprecated. Please, use Groebner[Basis].
[    2       2                                                  
[2 x1  + 3 x2  + 4 x1 + x2, x1 x3 - 3 x2 - 1, x2 x3 + 2 x1 + 4, 

           ]
  2 x4 + x3]

Second example:

ps:=[2*x1*x4^2 + 3*x1 + x4 + 6, x3*x4^3 + 2*x4^4 - 9*x3 - 18*x4, 2*x2*x4^2 + 3*x2 - 4*x4 + 1]:
js:={2*x4^2 + 3, x4^3 - 9}:
ord:={2*x4^2 + 3, x4^3 - 9}:

saturbasis(ps,js,ord);
           [       2                  
  "ps = ", [2 x1 x4  + 3 x1 + x4 + 6, 

         3       4                        2                  ]
    x3 x4  + 2 x4  - 9 x3 - 18 x4, 2 x2 x4  + 3 x2 - 4 x4 + 1]


                          /    2        3    \ 
                "js = ", { 2 x4  + 3, x4  - 9 }
                          \                  / 

                           /    2        3    \ 
                "ord = ", { 2 x4  + 3, x4  - 9 }
                           \                  / 

          [       2                  
 "qs = ", [2 x1 x4  + 3 x1 + x4 + 6, 

        3       4                        2                    
   x3 x4  + 2 x4  - 9 x3 - 18 x4, 2 x2 x4  + 3 x2 - 4 x4 + 1, 

      /    2    \           /  3    \    ]
   @z \2 x4  + 3/ - 1, 2 @z \x4  - 9/ - 1]


                      "zz = ", [2 @z, @z]

                      [            3          2    ]
            "aux = ", [2 @z, @z, x4  - 9, 2 x4  + 3]

Warning, grobner[gbasis] is deprecated. Please, use Groebner[Basis].
Error, (in grobner:-gbasis) invalid input: Groebner:-Basis expects its 2nd argument, tord1, to be of type Or(ShortMonomialOrder,name,MonomialOrder), but received plex(2*`@z`,`@z`,x4^3-9,2*x4^2+3)

I suppose that the "." is no longer used as it was back in Maple V3, and it seems that the author of the procedure was creating extra auxiliary variables to solve the problem.

What did the author use @ for creating the variables?  And how to fix the error?

Many thanks
 

Hello

I need to use the Ritt algorithm to find the characteristic sets of a set of differential equations. In the past, it seems there was a Maple package by D. Wang available through Maple Applications, but this no longer appears to be the case. I managed to download an old set of files from the author’s site, dated February 1996, which is a Maple V3 package. The instructions in the Readme file mention that using the provided Makefile, an m-file containing all the functions will be created, which can then be loaded into Maple. Unfortunately, running make -f Makefile did not create anything, so I am wondering if I could get some assistance on how to convert this package to something compatible with the latest Maple releases.

The source (txt) files are structured as follows:

Example: 

1) Comments
2) Definition of the User functions - something like

 

dcharsets[dcharset] := proc() `charsets/d_charset`(args) end:

dcharsets[dmcharset] := proc() `charsets/d_mcharset`(args) end:

dcharsets[dcs] := proc() `charsets/d_charser`(args) end:

dcharsets[dmcs] := proc() `charsets/d_mcs`(args) end:

dcharsets[dics] := proc() `charsets/d_ics`(args) end:

and

read `charsets.m`:

# set of non-zero remainders of d-polys in ps wrt d-ascending set as
#       user level function
`charsets/d_remset` :=

subs(`charsets/class`=`charsets/d_class`,
     `charsets/remseta`=`charsets/d_remseta`,
     `charsets/premas`=`charsets/d_premas`,op(`charsets/remset`)):

and lots of Maple procedures - Example below

 

`charsets/d_charset` := proc(ps,lst,medset)

....

end:

the source file ends with the following lines.

read dhelp;
save `dcharsets.m`:
quit

Many thanks

Note: Before posting this question here, I tried to contact the author but received no response.

Hello

Here is the ODE

sys := {diff(w(t), t) = y(t)*z(t), diff(x(t), t) = a*w(t), diff(y(t), t) = x(t)*z(t) + w(t), diff(z(t), t) = -x(t)*y(t), w(0) = w0, x(0) = x0, y(0) = y0, z(0) = z0}

with initial parameters a=2, w0 = -0.727367040, x0 = -0.728244724, y0 = -0.237753623 and z0 = 0.014225402.

With these parameters I have no problem to plot the solution.

nsys := subs({a=2,w0 = -0.727367040, x0 = -0.728244724, y0 = -0.237753623, z0 = 0.014225402},sys);

numsol := dsolve(nsys, numeric, method = rkf45);

vars:=[x,y,z,w];

with(plots):

col := [red, magenta, cyan, blue]:
display(
  seq(
    plots:-odeplot(numsol, [t, vars[i](t)], t=0..3, color=col[i], legend=vars[i](t))
    , i=1..numelems(vars)
  )
)

How to use animate (or explore?)  with a slider for each parameter (a,x0,y0,z0,w0)? And if I want to add a tfinal as well for the simulation (in place of 3)? ( I am newbie as far as using plot and related functions in Maple).  

Many thanks. 

Hello

Consider,  as an example,  the following (simple) transcendental equation. 

alpha*((epsilon-1)*x+y-3*x*z-epsilon/3*x^3+b*sin(w)+3)

How to retrieve the coefficients and the terms considering that the unknowns are x,y,z and w?   Something like [x,y,x*z,x^3,sin(w),1] and their coefficients.  

many thanks

Hello

I am trying to understand how to use Maple to solve a PDE.  Below it is a problem (Henon-Heilles system) where the answer is known.  

with(PDEtools);

infolevel[pdsolve]:=3:

declare(Hamil(x,y,u,v));

PDEHamil := u*diff(Hamil(x, y, u, v), x) + v*diff(Hamil(x, y, u, v), y) + (-2*x*y - x)*diff(Hamil(x, y, u, v), u) + (-x^2 + y^2 - y)*diff(Hamil(x, y, u, v), v) = 0;

pdsolve(PDEHamil)

Maple returns no solution, but one solution is:

sH:=1/2*(u^2+v^2)+1/2*(x^2+y^2-2/3*y^3)+x^2*y;

simplify(eval(subs(Hamil(x,y,u,v)=sH,PDEHamil)));
    0=0

What am I missing?

Many thanks.