Dear 

Hope everyone is good. I am face to attaine the converges solution of the attached problem. Please have a look and fix my problem. I am waiting your response

diverges.mw

I have 6 equations, eq1,...,eq6, with 6 unknowns a,b,c,d,f,g. I can find all the solutions with "solve".
If "solve" has found only one solution, then the ith solution number is given by sol[i]. For example,
c:=sol[3]. This comes from

sol:=solve({eq1,eq2,eq3,eq4,eq5,eq6},{a,b,c,d,f,g});

However, if solve has found more than one solution,
then the jth element of the ith solution is sol[i][j]. It is thus imperative to know how many solutions
the command "solve" has found. Also, how do we restrict "solve" to look only for real soultions?
Thank you very much!

mapleatha

I have a code in Maple that solves a system of polynomial equations (18 equations, 18 variables) using the command 'RootFinding[Isolate]' (it takes to Maple about 40 minutes to find all the solutions to the equations). Is it possible to see the implementation of the Isolate command? if not, is there any other open source code that implements the equivalent to Isolate command and also able to solve such equations? (I'm talking about the  numeric solutions. not symbolic).

I already tried to use the command 'solve_poly_system' in python (sympy package) which is open source. but the function didn't return a solution after a very long time (and I used a system of 9 equations and 9 variables which were much simpler than the equations Maple was able to solve using Isolate command).

I'm attaching the equations Maple solved using Isolate command. and also the equivalent in python with the simpler equations (that it wasn't able to solve).

solving_18_polynomial_equations.mw

trying_to_solve_polynomial_equations_python.txt

I'd appreciate any idea of how to use open source code that produces the same results as the code in Maple (if it's possible).

Thanks

Hey MaplePrimes

I have a problem with opening some of my documents in maple. When i try to open them, a box pops up with the text "How do you want to open this file?" with the options "Maple Text, Plain Text, Maple Inputs". None of these options work (document is blank) and "Plain Text" and "Maple Inputs" causes maple to crash. Is it possible to recover the documents?

ps. when i try to upload one the documents this happens:

 
Maple Worksheet - Error
Failed to load the worksheet /maplenet/convert/Maple_docs_til_mat.mw .

Download Maple_docs_til_mat.mw

Maple_docs_til_mat.mw
 

What is the meaning of the output of the command Weierstrassform?

E.g. what does mean x0^3 - 7*x0 + 88 +y0^2 ?

Maybe y0^2 = x0^3 + 7*x0 -88?

Hi 

I'm trying to find the equilibrium point by using DynamicSystem package here is my code:

pi := Pi; Cb := 1/(50*((1/1200)*220^2*2)*pi); ipu := 1200*10^6/(220*10^3*sqrt(3)); Fnom := 50; Rc := 0.3e-2*((1/1200)*220^2); Lc := (0.8e-1*((1/1200)*220^2))/(2*pi*Fnom); w := 2*pi*50; cf := 0.74e-1*Cb; scr := .2; z := .8; Ln := (1/1200)*z*sind(80)*220^2/(2*pi*Fnom); Rn := (1/1200)*z*cosd(80)*220^2; wlpll := 200; wb := 2*pi*50; kp1 := 1.27*ipu; kp2 := 1.27*ipu; ki1 := 14.25*ipu; ki2 := 14.25*ipu; kpll := wlpll/(3*wb); Tipll := 3^2/wlpll; kipll := kpll/Tipll; KpP := 1; KpQ := .1; Kp := 50; Kq := 5; wad := 200; Kad := 10; wlpP := 200; wlpv := 10; zv := .8; lv := (1/1200)*zv*sind(80)*220^2/(2*pi*50); rv := (1/1200)*zv*cosd(80)*220^2;
wPLL := kpll*atan2(ucqfT, ucdfT)+kipll*Gpll+w;
icdref := KpP*(u(1)-Pm/(1200*10^6))+Kp*GP; icqref := -KpQ*(u(2)-Vm/(0.17963e6))-Kq*GQ; ucdT := ucd*cos(thetaPLL)+ucq*sin(thetaPLL)-rv*(igd*cos(thetaPLL)+igq*sin(thetaPLL))+wPLL*lv*(igq*cos(thetaPLL)-igd*sin(thetaPLL)); ucqT := ucq*cos(thetaPLL)-ucd*sin(thetaPLL)-rv*(igq*cos(thetaPLL)-igd*sin(thetaPLL))-wPLL*lv*(igd*cos(thetaPLL)+igq*sin(thetaPLL)); Vd_c := ucd*cos(thetaPLL)+ucq*sin(thetaPLL)-w*Lc*icq*cos(thetaPLL)+w*Lc*icd*sin(thetaPLL)+kp1*icdref*ipu-kp1*cos(thetaPLL)*icd-kp1*sin(thetaPLL)*icq+ki1*Gd-Kad*(ucd*cos(thetaPLL)+ucq*sin(thetaPLL)-phid); Vq_c := ucq*cos(thetaPLL)-ucd*sin(thetaPLL)+w*Lc*icd*cos(thetaPLL)+w*Lc*icq*sin(thetaPLL)+kp2*icqref*ipu-kp2*cos(thetaPLL)*icq+kp2*sin(thetaPLL)*icd+ki2*Gq-Kad*(ucq*cos(thetaPLL)-ucd*sin(thetaPLL)-phiq); Vd := cos(thetaPLL)*Vd_c-sin(thetaPLL)*Vq_c; Vq := sin(thetaPLL)*Vd_c+cos(thetaPLL)*Vq_c; Upu := 0.17963e6;
icd := x__1(t); icq := x__2(t); ucd := x__3(t); ucq := x__4(t); igd := x__5(t); igq := x__6(t); Gd := x__7(t); Gq := x__8(t); thetaPLL := x__9(t); Gpll := x__10(t); ucdfT := x__11(t); ucqfT := x__12(t); GP := x__13(t); GQ := x__14(t); phid := x__15(t); phiq := x__16(t); Pm := x__17(t); Vm := x__18(t);
sys1 := [diff(x[1](t), t) = Vd/Lc-ucd/Lc-Rc*icd/Lc+w*icq, diff(x[2](t), t) = Vq/Lc-ucq/Lc-Rc*icq/Lc-w*icd, diff(x[3](t), t) = icd/cf-igd/cf+w*ucq, diff(x[4](t), t) = icq/cf-igq/cf-w*ucd, diff(x[5](t), t) = ucd/Ln-Rn*igd/Ln+w*igq-u__3(t)/Ln, diff(x[6](t), t) = ucq/Ln-Rn*igq/Ln-w*igd, diff(x[7](t), t) = icdref*ipu-icd*cos(thetaPLL)+icq*sin(thetaPLL), diff(x[8](t), t) = icqref*ipu-icq*cos(thetaPLL)-icd*sin(thetaPLL), diff(x[9](t), t) = wb*(kpll*atan2(ucqfT, ucdfT)+kipll*Gpll), diff(x[10](t), t) = atan2(ucqfT, ucdfT), diff(x[11](t), t) = ucdT*wlpll-ucdfT*wlpll, diff(x[12](t), t) = ucqT*wlpll-ucqfT*wlpll, diff(x[13](t), t) = u__1(t)-Pm/(1200*10^6), diff(x[14](t), t) = u__2(t)-Vm/(0.17963e6), diff(x[15](t), t) = wad*(ucd*cos(thetaPLL)+ucq*sin(thetaPLL))-wad*phid, diff(x[16](t), t) = wad*(ucq*cos(thetaPLL)-ucd*sin(thetaPLL))-wad*phiq, diff(x[17](t), t) = wlpP*(igd*ucd+igq*ucq)-wlpP*Pm, diff(x[18](t), t) = wlpv*(ucd^2+ucq^2)^.5-wlpv*Vm, y__1(t) = igd*ucd+igq*ucq, y__2(t) = igd*ucq-igq*ucd];
EquilibriumPoint(sys1, [u__1(t), u__2(t), u__3(t)], initialpoint = [u__1(t) = .97, u__2(t) = 1, u__3(t) = Upu, x[1](t) = 0, x[2](t) = 0, x[3](t) = 0, x[4](t) = 0, x[5](t) = 0, x[6](t) = 0, x[7](t) = 0, x[8](t) = 0, x[9](t) = 0, x[10](t) = 0, x[11](t) = 0, x[12](t) = 0, x[13](t) = 0, x[14](t) = 0, x[15](t) = 0, x[16](t) = 0, x[17](t) = 0, x[18](t) = 0]);

but I got this error..

 Error, (in DynamicSystems:-EquilibriumPoint) unable to convert the system to an explicit index 1 form.

anybody faced the same problem?

Thanks,

Hey everyone
 

I am trying to create a procedure, which includes a part, where a function is plotted. I want to be able to declare the range of the plot within the procedure parameters as x=range - example when executing: procedureName(function,x=range). I have isolated a small part of the procedure and the different approaches I have tried:

For simplicity's sake let's call the procedure test.

test:=proc(function,{x::range:=0..1})

#I would then like to be able to plot the following:

plot(function,'x'=x);

end proc:
 

However, the single quotes do not prevent x from being evaluated within the procedure, and there interprets the second argument of 'plot' as 0..1=0..1. Another approach I tried was the following:

test:=proc(function,{x::range:=0..1})

local xRange:=x;

unassign('x');

plot(function,x=xRange);

end proc:

However, I run into the same problem as above - the elements within the single quotes are still evaluted within the procedure. A workaround would be to simply rename the range parameter, for example:

test:=proc(function,{xInr::range:=0..1})

plot(function,x=xInr);

end proc:

I would really like to be able use x as the parameter, though.

Thanks in advance!

Dear Maple users,

I have a big exporession in the form f(s)/g(s) where f and g are polynomial involving irrational coefficients. Both f and g consist of hundreds of terms. One way to get the inverse laplace is to factor the expression and then take the invlaplace.

The code is as follows:

with(inttrans):

p:=factor(f(s)/g(s));

sol:=invlaplace(p,s,t);

I get sol as a function of time, which gives satisfactory result for t=0 but  grows bigger and bigger with increasing value of time. From the limit theorum I see that  Limit (s*f(s)/g(s)) as s--> 0 is finite, which means that the invlaplace is not correct at very large value of time.

What is the error in the process?

Thanks,

Hi all,

I attached a program here and the desire is the calculation of Nu.As you could see through the attached file, the F2(r) function contains an 'integral' which makes it difficult if I want to calculate F2(r=1) and it goes the same for D(F2)(r=\phi). So I firstly corrected the F2(r) function as FF2(r) in which the parameter R is calculated in the top of the file. Afte I replace the values of \phi and 1 in the FF2(r) not in F2(r) just because of the integral. The Nu is calculated finally, but it differs from the initial guess. How could I make a loop in order to correct the initial guess by replacing the first Nu calculated in the end of the program??

Ther is a problem and that is the "k" which must be entered in this part in each loop:

Digits:= 10:

K:=Nu->( k )

I do not know whether or not it is possible to change it so that the program identify the 'k' and replace it in the "K:=Nu->( k )" for k.

SolveCode.mw
 

Hi,

I am collecting first order terms in psi and phi in the following expression.

Basically I want to keep coefficients for which (power of phi + power of psi) < 2 and ignore the rest.

Here, H, a, psi, phi are all functions, not variabels.

I tried following answer but it doesn't work due to derivatives.

https://www.mapleprimes.com/questions/37228-Ignore-Terms-Above-Particular-Orderpower

(Error, selecting function must return true or false)

Thanks a lot,

Rahul

Dear all

How can I finish the attached code and I plot   the set of points (x[i],y[j], U[i,j]) 

U[i,j] represent the value of U at the position  (x[i],y[j])

Many thanks for your help

Plotsetofpoint.mw

Before Maple 2015, units were enlosed in [[ double brackets ]] when displaying 2D input and output. In later versions these brackets are displayed only when editing input, and never in output, which in my opinion detracts from readability. Does anybody know if it is possible to revert to the old behaviour?

Here is my code:

with(DEtools): with(plots): with(linearAlgebra):

DE1 := diff(y(x), x) = d^3*y(x)/dx^3+3*d^2*y(x)/dx^2+4*d*y(x)/dx+12*y(x);

DEplot(DE1, [y(x), x = 0 .. 5][[y(0) = -3, (D(y))(0) = 0, ((D^(2)(y))(0) = 0, ((D^(3)(y))(0)]]);

I get the Error message: Error, (in DEtools/DEplot) called with too few arguments

Any help would be greatly appreciated, thanks.

Hi I have a function i d live to plot and integrate but maple tells me there is a probleme with the range when i want to plot and will not give me a numerical value of the integral :

What am i doing wrong ??

I am trying to repeat the 'first example' in Stephani & MacCullum, Differential equations see chapter 16 and (16.5).  The differential equation is,

pde := b1(x, y)*(diff(u(x, y), x))+b2(x, y)*(diff(u(x, y), y)) = 0

and I would like to compute DeterminingPDE.  The textbook answer is linear in b1 and b2 (as my 'by hand calculation' is) but Maple's,

DeterminingPDE(pde)

contains quadratic terms such as b1^2, b1*b2 etc.  I don't understand the appearance of the quadratic terms.  Is it possible for Maple to return an answer which is linear in b1 and b2?