Hello,

When i try to open my 583 KB maplefile in maple 2017, a box shows up, asking: "How do you wanna open this text file?"  with 3 options. No matter what option i pick, a white empty page shows up. I have windows 10 and office 2016 installed on my PC.

This is the second time this problem happens to me, and both times have i lost hours of work. I have red multiple chats of people with the exsact same problem trying to get support from MaplePrime, but unfortunately, you have never been able to repair the files or find the source of the problem. 

Is this problem related to Maple 2017 or why does this happen? how can I trust Maple not to "loose" my work a third time?

My file: Download Hjemmeopgavesæt_2.mw

Kind regards Anna

Is there a way in Maple to numerically integrate (with some symbolic variables retained), involving vectors?

Alternatively, is there a way to simply numerically integrate the following expression involving vectors, without any remaining symbolic variables remaining?

Integrate over vectors p1, p3
(with vector x remaining as free variable after integration)
( e^{-i p1 . x} (p1² + p3²) )  / ( (p3 - p1)² (p3²*a² +1)² )

If absolutely required for numerical integration, i.e. no other way to get maple to perform a semi-numerical integration, then vector x, and the scalar variable "a" can also be specified a value, but x should remain a vector. 

Of course, if the integration above can be done analytically, or even partly analytically (e.g. if the vectors are expressed in spherical polar co-ordinates, and some of the variables like Sin \theta etc. can be integrated over), that would be very useful as well. 

 I wand to plot the following expression involving an imaginary number. Can I get some help??

((1/10)*exp((2/135)*sqrt(-11)*sqrt(225)*t-(2/3*I)*x+1/15)/((3/10)*exp((2/135)*sqrt(-11)*sqrt(225)*t-(2/3*I)*x+1/5)

Hi,

I am trying to complete this assignment but I am having trouble on this question. It is asking me to use a graphical approach to estimate a 𝛿 > 0 such that for all x...

0 < | x - c | < 𝛿 implies that | f(x) - L | < ε

It says I can do this by plotting my f(x), y₁, and y₂ over the interval [c - 𝛿, c + 𝛿] with a y-range of [L - ε, L + ε]. y₁, and y₂ are banding lines defined by ( L - ε ) and ( L + ε ), respectively. The value of ε is shown below. I dont know where to start but this is what I have so far...

f(x) := ( x ( 1 - cos(x) ) ) / ( x - sin(x) );

The limit ( L ) of this function as x approaches 0 ( c = 0 ) is...

L := ( limit ( f(x), x = 0) );

The limit is 3 ( L = 3 ).

 ε = r = Student Id / 5000000   = 0621748 / 5000000   = 155337 / 1250000

 ε := 155337 / 1250000;

y₁ := ( L - ε );

y₂ := ( L + ε );

Originally, it had asked me to graph the function with the banding lines (y₁, y₂) together within the interval [-0.2, 0.2], which I have done. I just do not know how to find a value for 𝛿 in this case. Please help.

Thanks.

abs(-((-(1/20)*sqrt(5)-1/20)*cos((1/5)*Pi)-(1/20)*sqrt(2)*sqrt(5-sqrt(5))*sin((1/5)*Pi))*24^(1/5)*5^(3/5)-I*((1/20)*sqrt(2)*sqrt(5-sqrt(5))*cos((1/5)*Pi)+(-(1/20)*sqrt(5)-1/20)*sin((1/5)*Pi))*24^(1/5)*5^(3/5))

I am trying to compute the modulus the above complex number. However, the "abs" command does not affect the complex expression. Any reason for this?

Many thanks!

Hello,

I'm writting a Modelica External component which use a C function, like this :

model SAMS.BlockUdpReceiver
    parameter Integer relativeSockId = 0 "Relative socket id (0..10)";
    parameter Integer stateUdp = 2 "state of receiver 1=receive data from udp ; 2=state from recorder config file";
    parameter Real step_time = 0.05 "sample time in second";
    parameter Integer nbDouble = 3 "number of double value to send";

    function udpReceiveDataMapleSim
        input Integer relativeSockId;
        input Integer stateUdp;
        input Real step_time;
        input Real currentTime;
        input Integer nbDouble;
        output Real dataToReceived[nbDouble];
    external "C"udpReceiveDataMapleSim(SAMS.BlockUdpReceiver.udpReceiveDataMapleSim.relativeSockId, SAMS.BlockUdpReceiver.udpReceiveDataMapleSim.stateUdp, SAMS.BlockUdpReceiver.udpReceiveDataMapleSim.step_time, SAMS.BlockUdpReceiver.udpReceiveDataMapleSim.currentTime, SAMS.BlockUdpReceiver.udpReceiveDataMapleSim.nbDouble, SAMS.BlockUdpReceiver.udpReceiveDataMapleSim.dataToReceived)
            annotation (
                Library = "F:/SAMSSVN/workspaceMaple/SamsLibrary/x64/Debug/SamsDll.dll",
                __Maplesoft_callconv = "stdcall");
    end udpReceiveDataMapleSim;

    Modelica.Blocks.Interfaces.RealOutput dataReceived[nbDouble] annotation (Placement(
        visible = true,
        transformation(
            origin = {120, 50},
            extent = {
                {-20, -20},
                {20, 20}},
            rotation = 0),
        iconTransformation(
            origin = {110, 50},
            extent = {
                {-10, -10},
                {10, 10}},
            rotation = 0)));
equation
    when {initial(), sample(0, step_time)} then
        dataReceived = udpReceiveDataMapleSim(relativeSockId, stateUdp, step_time, time, nbDouble);
    end when;

    annotation (
        Diagram(coordinateSystem(extent = {
            {-100, -100},
            {100, 100}})),
        Icon,
        experiment(__Maplesoft_engine = 2),
        __Maplesoft_none);
end SAMS.BlockUdpReceiver;

I want MapleSim to call C function at initial() time and with a sampled period of step_time.

But, the function is called at each simulation step (here at 0.4 ms)

for demonstrate it, I print a log file each time the function is called.
this is a part of the result :

id Receiver =11 ; CurrentTime = 0.151200 while t_step=0.002000
id Receiver =11 ; CurrentTime = 0.151200 while t_step=0.002000
id Receiver =11 ; CurrentTime = 0.151200 while t_step=0.002000

id Receiver =11 ; CurrentTime = 0.151600 while t_step=0.002000
id Receiver =11 ; CurrentTime = 0.151600 while t_step=0.002000
id Receiver =11 ; CurrentTime = 0.151600 while t_step=0.002000

id Receiver =11 ; CurrentTime = 0.152000 while t_step=0.002000
id Receiver =11 ; CurrentTime = 0.152000 while t_step=0.002000
id Receiver =11 ; CurrentTime = 0.152000 while t_step=0.002000

Why C function is called so many time (3 times in a step), and why is called for each simulation step (0.4ms) instead of each 2 ms ?

Maybe I make a bug in my Modelica code ? or not ?

thanks for any reply.

restart;
globale values, small water droplet in gravity field  , through air with velocity V=[vx,vy]  ,v=abs(V)  total dragforce kan be written FDD=abs(FD)

mu := 0.18e-4; rho := 1, 2; d := .2; Co := .4;
#abs(FD) divided into  FDx og FDy
%;

FDx := (3*Pi*mu*d+(1/8)*Pi*Co*rho*d^2*abs(v))*vx;




FDy := (3*Pi*mu*d+(1/8)*Pi*Co*rho*d^2*abs(v))*vy;

# Define v=[vx,vy] to abs(v) wich gives the length of v (scalar value)


v := proc (vx, vy) options operator, arrow; (vx^2+vy^2)^.5 end proc;

#Make FDx og FDy to  abs(FD) 

FD := sqrt(FDx^2+FDy^2);

#Define total dragforce

FDD := (1/8)*Cd*abs(v)*Pi*d^2*abs(v^2);

#Total dragforce can be writte like FDD=abs(FD), solve for Cd(v)

FD1 := solve(FD = FDD, Cd);

#Make a function which returns Cd(v) 

Cd := proc (v) options operator, arrow; 63.66197724*FD1/abs(v)^3 end proc;

HOWTO GET MY Cd(v) to return values ?????

Ive got some problem understand the use of = and := , and how to get my Cd function to mangage the v expression. A copy (in norwegian) from my assignment to see the formulas is attached. Im thankfull for any help.

inl1d.pdf

The context.

I have to numerically integrate a complicated function over a wide x domain: int( f(x), x=0..2e8). Because of the characteristic of the function, to get accurate results, I must separate thi x domain in about 5000 sub-intervals. With a do loop doing 5000 iterations I apply the 'int" commant 5000 times and I add the results. In fact, in the do loop I use this specific command:

evalf(Int(fct(k0), k0 = j*interv .. (j+1)*interv, method = _Gquad, 'epsilon' = 1e-3))

The value of interv is 30000 and j goes from 0 to about 5327 by 1.

The problem.

At the beginning of the computation (for small values of j) the time needed to Maple to perform one loop is about 3.5 seconds. The problem is that loop after loop, this time always increase from 3.5 seconds up to 600 or 800 or even 1000 seconds. It then becomes prohibitive. (I have many of these computations to perform. It is a heavy computation that would need about 6 hours at 3.5 seconds per cycle. I let my computer work overnight. But at 800 seconds per cycle it would need weeks).

More information.

Sometimes, without any visible reasons, this time decreases back to 5 or 6 seconds per cycle and re-increases again. One can think that it depends on the local characteristics of the function, but if I stop the computation at any point (particularly when the time per cycle is large), re-insert the results already obtained at this point and restart the computations at this point, the time per cycle goes back to about 3.5 seconds and slowly increases again. It is like garbage accumulates somewhere and slows down Maple. When I stop Maple and restart it "flushes" this garbage.

I tried.

I have searched the net, MaplePrimes, Maple help… to solve it. I tried the command gc() even if it is not recommanded with no results. I use a MacBookPro i7 quad core 3.3 GHz with 16 Gig of RAM.

These computations use at most 1 or 2 Gig. When I do the command kernelopts(datalimit) I get infinity as the result. Then I presume that Maple have access to the full 16Gig of RAM (minus what is needed bye the system). (The same problem appears on different machines, Windows or Mac).

My question is very simple. What causes this problem and how can I solve it?

(Yes I could switch to a pure numerical computations software (C, fortran, MatLab…) but for some reasons I have to do that with Maple.) I have been a Maple user for about 30 years and never had that kind of problem.

Thank you very much.

Normand Beaudoin, Dept. of physics &astronomy. University of Moncton.

Dear Sirs, 

Can someone explain to why if I load Real Domain, that the derivate of a function at certain value comes out like in screendump? 

Thanks in advance :)  

https://imgur.com/a/sHJEj

Fred

I have this set of four equations and five constants, how I will shoot for x5 to find the unique solution

I assumme x5= pi/2 as initial guess but no solution

any body can help?

I am writing a textbook in biomedical engineering and using Maple 14 for generating figures.  In many of the graphs, my axis labels have subscripts or superscripts.  For example in a 2D plot statement I type   labels=[x,f[0](x)] which gives a subscript 0.   However, both x and f₀(x) appear in italics.  How can I have them appear as normal...i.e. without italics? The labelfont command does not seem to have an instruction to remove the italics.  Can you assist me?

I would like to solve {x^2+y^2+z^2 = 3, x+y+z = 3} over the reals. Clearly x=1,y=1,z=1 is a solution.

Maple seems to have a hard time with this. I have tried using with(RealDomain) and various commands.

The last solution  is getting closer to the real number answer if i substitute z = 1, but then i get the strange answer { 1=1, x=1,y=1}

I tried using wolfram and it showed me the correct answer.

Rest assured, I am a strong maple fan. I sometimes use wolfram for quick and dirty solutions.

Also is there a way to turn off "with(RealDomain)", switch back to the default domain, without using 'restart'. 

Is there any way i can define a value to a variable together with an angle? 

I am looking to do something like this:

the example is from Mathcad, but i was hoping there was some way to do it in Maple also?

I want to write a code for solving following PDE with Cauchy data.
Equation:  (y-u(x,y))*(diff(u(x,y), x))+(u(x,y)-x)*(diff(u(x, y), y)) =x-y
Cauchy Data: u(x,y)=0 on xy=1.

THE CODE:
restart;
PDE := (y-u(x,y))*(diff(u(x,y), x))+(u(x,y)-x)*(diff(u(x, y), y)) =x-y;ic:=u(x, 1/x)=0;
ans := pdsolve({PDE,ic});
pdetest(ans, PDE);

Maple doesn' t give a solution.Why?

"Error, (in PDEtools:-Library:-NormalizeBoundaryConditions) unexpected occurrence of the variables {x} in the 2nd operand of u(x, 1/x) in the given initial conditions"

I

How to get the number of parameters of an operator/procedure? Like this.