Maple 18 Questions and Posts

These are Posts and Questions associated with the product, Maple 18

Hello, I found this very strange behavior in Maple and I can't explain why this is not working

A little bit of context first:

1. I placed a polygon as a boundary for a section and then two polygons that correspond to inner holes to the first one.
2. Then I proceed to create a regular mesh that places N x M points spread across the region (OK here)
3. A procedure checks weather or not a Point is inside the region, on the borders or in the inner holes (OK here)
4. Then I want to select the closest (but exterior) ones so I can create a path using the mesh points.

Here is where I find the issue. I start at a vertex called V[1,1] and I want to arrive at V[1,2] (in the document they are blue solid points marked they are near-vertices near the original polygons). The procedure that I apply finds a path towards the V[1,2] as I was expecting but when the procedure hits the V[1,2] coordinates the while loop does not stop

The condition I wrote was:    while point<>V[1,2] do  where 'point' is correctly generated by another procedure.

This happens in a 40 by 50 mesh but with other configurations it works properly (there are also another kind of errors but it's inherent to lack of optimization in my procedures).

What baffles me is why doesn't it stop the cycle, if I test the condition outside the loop it DOES recognize the points are indeed equal. Is it something in Maple or is it something in my PC?

Thanks to anyone who can see the error or the problem because I don't understand the nature of the problem.

Problem with pdsolve/numeric


I created a routine for solving a thermo-mechanical problem. The size of the spatial domain is a function of time and the thermo-mechanical behavior of the structure.

The solution is obtained by discretizing the time domain in n intervals. The thermo-mechanical responses are obtained at each time t[i] =t[i-1]+dt.

The material exhibits elastic and elastoplastic mechanical behavior and thus the problem was divided into two consecutive phases (phase 1 and 2).

The heat problem is nonlinear because the thermal properties are variable (termal conductivity, specific heat, and density).


The problem:

In phase 2, the pdsolve/numeric command returns an error for the solution of the heat conduction equation (equation called pde1). I believe this error is related to the derivative of thermal conductivity k(x1) (piecewise function).

I tested many alternatives (I wrote the pde1 equation in two different ways), I checked the routine many times and I don't understand the reason for the error. With each attempt, the command returns a different error.

Thanks for your attention and help.

Please can someone help me out, have been trying for a very long time now on how to differentiate the lines on the graph.......please find attachment below and correct..................................................................


# Define the ODE system
  odeSys:= { (diff(F(eta), eta, eta, eta))*(1+epsilon-alpha((diff(F(eta), eta, eta))^2))+F(eta)*(diff(F(eta), eta, eta))+S*(diff(F(eta), eta))-(1/2)*S*eta*(diff(F(eta), eta, eta))-(diff(F(eta), eta))^2-M*(diff(F(eta), eta)), (diff(theta(eta), eta, eta))*(1+R)-delta*(diff(F(eta), eta))^2-Pr((3/2)*S*theta(eta)+(1/2)*S*eta*(diff(theta(eta), eta))-2*(diff(F(eta), eta))*theta(eta)+F*(diff(theta(eta), eta)))};
# Define the first set of boundary conditions
  bcs1:= { F(0) = 0, (D(F))(0) = 1, (D(F))(inf) = 0, theta(0) = 1, theta(inf) = 0

  RVals:=[0.1, 0.5, 1]:
  for k from 1 by 1 to numelems(RVals) do
      pList:=[ epsilon = 0.18, M = 0.5, S = 1.5, delta = 0.3, Pr = 1.5, alpha = 0.4, R = RVals[k],inf=1
      sol1[k]:= dsolve( eval
                        ( `union`( odeSys, bcs1),
  ( [ seq
      ( odeplot
        ( sol1[i],
          [eta, theta(eta)],
    color = [red, green, blue],
    title = typeset( theta(eta), " versus ", eta),
    titlefont = [times, bold, 20]

Could anyone help me out to convert the equation into differential transform method



My question is quite simple yet maybe a bit hard since I understand that messing around with series can lead to dead ends.

Given a certain general term, for instance sum(x^n/n!,n=0..infinity): Can Maple recognize which function does it come from (in case such analytic function is known)? in the example I would expect it to return exp(x).

Thank you very much.


 Good morning all.
Consider $A=[a_{i,j}]$, a $18\times 18$ matrix (for example); the integer entries are randomly chosen in $[[-5,5]]$ (for example). In general, $A$ has distinct eigenvalues.

I seek the eigen-elements of $B=Transpose(A^{-1})A$ with $10$ significand digits (for example); in general, $B$ is diagonalizable ($P^{-1}BP=D$, a diagonal complex matrix). I use the command $evalf(Eigenvectors(?))$.

Many randomized tests require working with hundreds of Digits. The worst one requires $629$ digits!! Moreover (in this test), when $Digits:=400$, the condition number of $P$ is $10^{118}$ and , with $Digits:=619$, the condition number drops to $376$.

I am surprised by this instability. In particular, this method seems to be unusable when $n=100$.
Does there exist a method (using maple) which allows to solve the problem without dragging behind me a multitude of digits ? (perhaps with iterations...)
Thanks in advance.


Dear friends, please I would like to ask for your help with the following problem: 

I have to compute some linear programming calculations. I thought it would be a good idea to perform them employing a parallel code. However, much to my surprise, the parallel code is slower than the single-threaded one. I enclose a worksheet sketching both codes with an example. Would you please tell me what it could be wrong with my code? 

Many thanks for your help.EXAMPLES.mws 

Please can you help me in resolving this error?

Here is the


I have a nonhomogeneous heat conduction problem, where the thermal conductivity, the density, and the specific heat of the
material are piecewise functions.

The thermal conductivity derivative has a discontinuity that causes a problem in the pdsolve command (see the first test).

To avoid this problem, I did a second test where the product rule was calculated directly.

Is there a better way to deal with this problem?

thank you

I integrate the expression maple but the result is large. How to reduce the size of the result? Also, what is dilog on maple?

u=a-(4*i*b)*(a*sinh(c)-2*i*b)/(a+2*i*b*sinh(c)), where b is a complex parameter, a is a real constant and, c=\sqrt(a^2-4*b^2)*(x+t/(2*b^2)), then how to calculate |u|^{2} on maple?

Hello there, 

Here is a set


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