Hello,

I would like to solve this kind of system with any numeric method.


With any kind of IBCs.

My code :

Maple says : Error, (in pdsolve/numeric/plot) unable to compute solution for t<HFloat(0.0):
matrix is singular
Error, (in pdsolve/numeric/plot) unable to compute solution for t>HFloat(0.0):
matrix is singular

Any idea why ? Any help ?

Thank you

a curve has residual p if it is linked, in a complete intersection, to a curve with residual p-1

0 residual if is a complete intersection of two surfaces

do complete intersection means two surfaces totally overlapped?

why they are not the same one if complete intersection?

how to test whether a curve  lies in no plane in maple?

Hello,

I am trying to make c (0.001<=c<=0.02) a random value at each time step.But with my code c is choosing randomly from the interval then solveing the equation for fixed c at each time step.

How can I mack c a diffrent random value at each time step?

This is my code:

> with(DEtools); with(plots);
>
> Ra := RandomTools:-Generate(distribution(Uniform(0.001, 0.02))); c := Ra;
> f := .1;
>
> eq := diff(X(t), t) = 1-f-c*X(t);
>
> init := X(0) = 100;
>
> sol := dsolve({eq, init}, {X(t)}, range = 0 .. 100, numeric);
>
> odeplot(sol, [[t, X(t)]], t = 0 .. 100);

Thank you

I have a rather complex expression that I want to find the zero for as a function of two other parameters, i.e. I have a function

Denom := (s,M,g) -> stuff

that I want to find the zero of for a variety of values of M and g. In some cases the solution will be complex, which is entirely acceptable. However, the real part of the solution should never be negative, and yet that is the kind of result I am getting.

As an example (illustrated in the worksheet, when attempting to find the zero for M = 3 and g = 0.2, fsolve gives me s = -6.1 -1.4i. However, when I plot the function with the parameters input already, I can clearly see a zero at s = 9 with no imaginary component. Why won't fsolve find this zero? How can I make it do so?

See the bottom of the attached worksheet for the main problem.

 pole-dragging-mapleprimes.mw

Hi all,

I'm currently writing a code to solve the equations for a gravitational collapse of a star numerically. I'm using two dimensional Arrays for most of the physical quantities in my finite difference equations, with one index for the spatial dimension (I'm only considering spherically symmetric collapses) and one time index. I wrote two nested loops, where the inner one solves the equations from the centre of the star to the surface (with the exception of one quantitiy, where I have to integrate the other way around) and the outer loop advances the Arrays in time. My problem is, that Maple doesn't seems to evaluate the two dimensional Arrays. Instead for inserting the appropriate value for e.g. A[3,2], Maple just keeps on using A[3,2] which messes up some formulas, since I have to take roots of the numbers. At least that is what seems to be going on when I'm trying to debug the relevant part of the code and I check for the values, with whicih Maple calculates. I'm also using a one dimensional Array to store the timesteps, I'm using in the code and Maple doesn't seem to have problems evaluating them. Is anybody familiar with this problem? Does Maple have trouble with multidimensional Arrays in loops or have I just messed up my code? I have uploaded my code (I hope it worked). I apologize for my code being messy, but it's the first time I'm working with Maple and using numerical methods. The part which troubles me is labeled "# actual code".

Thank you all.

Oppenheimer-Snyder_Maple_3.mw

Hello People in Mapleprimes,

I have a question about the codes in the help page of assign.

Please tell me about this.

The folliowing codes were written there:

code (A)

assign(a,c):

assign(a=d,b=2):

a,b,c;

The output of these was 

d,2,d

I think that assign(a,c) means assign(a=c) or a:=c, not c:=a.

If what I wrote was true, the output of the above code should be

d,2,c.

And, if I changed assign(a,c) to assign(c,a), the output was d,2,d, which is the output written on the helppage 

of the assign. On the other hand, the output of code A was surely d,2,d.

Why does assign(a,c) have the same meaning as assign(c,a)?

Best wishes

taro

Hello everyone, I am having problem while trying to evaluate the double integral written in the file attached double_inegral.mw. Please help me out.
Many thanks in advance.

I am getting different results when determining the eigenvectors of a simple beam vibration problem in 2 ways :

See attachment :
1) When generating a matrix with GenerateMatrix([eqs..],[A,B...]) , or with
2) reformulating the same matrix by hand with S:=Matrix(4,4,[[ ]]) I get different eigenvectors for actually the same matrices ?

Tried already commands like 'convert' , 'Normalize', setting precision, to no avail.
Is this due to rounding ?

Any suggestions ?

Thanks ! 

Eigenvectors_2.mw

In this work we show you what to do with the programming of Embedded Components applied to graphics in the Cartesian plane; from the visualization of a point up to three-dimensional objects and also using the Maple language generare own interactive applications for touch screen technology in mobile devices techniques. Given that computers use multicore and designed algorithms that solve calculus problems with very good performance in time; this brings programming to more complex mathematical structures such as in the linear algebra, analytic geometry and advanced methods in numerical analysis. The graphics will show real-time results for the correct use of the parallel programming undertook to bear the procedural technique is well suited to the data structure, curves and surfaces. Interaction in a single graphical container allowing the teaching and / or research the rapid change of parameters; giving a quick interpretation of the results.

FAST_UNT_2015.pdf

Programming_Embedded_Components_for_Graphics_in_Maple.mw

Atte.

L.Araujo C.

Physics Pure

Computer Science

Hi there,

How can I plot the equation $r=1/theta$ in polar plot in maple13? and in general for plotting $r=1/(theta-alpha)$ alpha is constant.?

 Any help will be appreciated.

Regards

Yegan

I tried to run a few calculation on maple, the numerical output is, e.g.

0.3 10^(-5)

Is there any simple way to set it as 0.3e-5? I am not intened to write the data into a file, hence, i am not sure if writedata is a suitable option.

Thank you very much! 

So as the title claims I am new to maple and am having trouble with trying to learn how exactly to accomplish certain things.

Mainly being that I am having trouble with a set of exquations that are equal to zero which I then set equal to eachother in order to solve for the values of the variables (x,y)

for example lets say that

f1:= x³-x²-(y²-y)x = 0

f2:= -1-ln(y)+ln(x-y) = 0 

now from here I start to become a bit iffy on what exactly I am supposed to be doing. I have a line of code stating 

f3:=f1=f2

and from there I have had absolutely no luck what so ever. 

any help would be much appreciated.

Hello!

I wanna ask you the next question.

I have system of four linear differential equations and solution of it (four functions f1,f2,f3,f4). When I try to verify my solution by odetest() I get a set of values: 0 and two bulky expressions with imaginary units.

So, I can't understand exactly my solution is right or not?

sysODE:={bla bla bla}{f1,f2,f3,f4}(x);
solsysODE:={f1(x)=........,f2(x)=......,f3(x)=......,f4(x)=.......};
misalign:=odetest(solsysODE,sysODE);
nops(%)
3
op(1,misalign) # zero
op(2,misalign) # not zero
op(3,misalign) # not zero

Thank you!

The expression

A := (a/u*(y*exp(-y) - x*exp(-x))/(y-x) + b/u) / (c/u + d/u);

is obviously equivalent to

I typed the latter by hand since I don't know how to do it in Maple.  Is there a trick to get Maple to do the simplification as shown?