Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

This is simplified from a larger example.  I never saw Maple exit from a numercal calculation.

> 123456789 ^ 987654321:
Execution stopped: Stack limit reached.

Process Maple R2016 exited abnormally with code 158

> kernelopts(maxdigits);
                                  38654705646

> lprint(123456789. ^ 987654321.);
.4339566080e7991619731

kernelopts(memusage) shows about 2~3 meg bytes used.

The system has 16G Ram.  16G swap.

Seems like something maple should have caught.

I don't know where to ask this.  Sorry if this is the wrong forum.

I use maplev-mode

;; Version:    2.155
;; X-RCS:      $Id: maplev.el,v 1.14 2006-06-02 14:02:38 joe Exp $
 

I am attempting to modify it so
  f1 invokes maplev-cmaple-send-line
  f2 invokes maplev-cmaple-send-region
  f3 invokes maplev-cmaple-send-buffer
 

tried adding
(define-key map [(control c) (control c) ?l] 'maplev-cmaple-send-line)
(define-key map [(f1)]  'maplev-cmaple-send-line)

but, emacs seems to not recognize this.  I can change the global keymap to get this behavior.
Is there a way to do this in maplev.el?
 

Tom Dean

What can i do in this case? I,m traying solve a system of non linear equation like this, i want to know Rs and Rsh:


I want to solve the following non linear PDE

SS := [diff(u(x, y, t), t)-0.625e-1*(diff(u(x, y, t), x, x)+diff(u(x, y, t), y, y))-6*(diff(u(x, y, t)*(diff(v(x, y, t), x)), x)+diff(u(x, y, t)*(diff(v(x, y, t), y)), y)) - 2*(u(x, y, t))(1-u(x, y, t))=0, diff(v(x, y, t), t)-(diff(v(x, y, t), x, x))-(diff(v(x, y, t), y, y))+16*v(x, y, t) -u(x, y, t)=0]

when i use the command

sol := pdsolve(SS, [u, v], singsol = false)

maple give the error message

Error, (in pdsolve) found the independent variables {t, x, y} also present in the names of the functions of the system []

 

I have the following fuction in Laplace domain,

restart:with(plots):with(inttrans):

u:=Pi^4*s3^(alpha-1)/((s1^2+Pi^2)*(s2^2+Pi^2)*(-s1^2+Pi^2*s3^alpha-s2^2))-Pi*s1*s2^(alpha-1)/(s3*(1+s2^alpha)*(-s1^2+Pi^2*s3^alpha-s2^2))-Pi*s1*s2^(alpha-1)/(-s1^2+Pi^2*s3^alpha-s2^2);

Where, s1, s2, s3 are the Laplace variables.

x1:=invlaplace(u, s1, x);

This worked. But the next two doesn't work.

y1:=invlaplace(x1, s2, y);

uu:=invlaplace(y1, s3,t);

Even, I tried to plot the unevaluated invlaplace but no luck.

alpha:=1:t:=1:
plot3d(uu,x =1..2, y=1..2);
 

Am I missing something?

 

Dear all,

I have the following question, this code:

restart:
with(DifferentialGeometry):
DGsetup([w1,w2],N):
eq1 := ExteriorDerivative(w1);  
eq2 := ExteriorDerivative(w1) &wedge ExteriorDerivative(w2);
eq1 &wedge eq2;

Gives the error:
Error, (in DifferentialGeometry:-Tools:-DGzero)  given degree, 3, exceeds that of frame dimension, 2

Unfortunately, I am not so familiar with differential geometry but as far as I know dw1 \wedge  (dw1 \wedge  dw2) = 0 should be correct.

Thank you for your help
best
baustamm1

I am looking for persons with experience in setting up maple for the blind. The setting is a 21-year old blind
 student who wants to do math. He uses Mac OS/X and the built-in VoiceOver screen reader, plus refreshable Braille display (one-line), a Braille printer, and Nemeth, the Braille extension for math symbols.

Initially, we are working from no experience whatsoever, trying ideas, mostly failure. Getting some advice from persons who are blind and using maple would be wonderful. If anyone knows of an instance, a person who is blind and regularly uses maple, then we would both would be delighted to receive advice on what to install, how to set it up, and how to use maple on a daily basis.

One trouble for the VoiceOver screen reader is verbosity of maple output. Any methods to reduce the amount of output would be welcome. To uderstand the issue, look at the output of these two commands when interface(prettyprint=0) has been set to help out the VoiceOver screen reader:

matrix([[1,2],6,7]]); Matrix([[1,2],[6,7]]);

The first outputs the same text, which VoiceOver will read accurately. The second dumps out two lines of extraneous and confusing information, only 20% of which is useful. The verbosity is not restricted to matrix packages linalg or LinearAlgebra. It is a problem wtih nearly all packages.

-Grant Gustafson, Salt Lake City, Univ of Utah Math Dept

 

 

Dear friends:

I am facing two problems

1. one is to get solution of the below system of ODE for L=100 (highlited as red) and

2. the other is I want the graph in the form of solid line not poit, asterisk etc.

 

restart; epsilon := .1; Pr := 1; beta := .1; Sc := 1; S := 1; L := 20;
for i from -L while i <= L do;
a[i] := 1.0*i/L;
end do;
for i2 from -L while i2 <= L do;

fw := a[i2]; 

Eq1[i2] := eval(diff(F(eta), eta, eta, eta)+F(eta)*(diff(F(eta), eta, eta))-(diff(F(eta), eta))^2+S*(epsilon-(diff(F(eta), eta)))+epsilon^2);
Eq2[i2] := eval((diff(G(eta), eta, eta))/Pr-G(eta)*(diff(F(eta), eta))+F(eta)*(diff(G(eta), eta))); 
Eq3[i2] := eval(diff(H(eta), eta, eta)+Sc*(F(eta)*(diff(H(eta), eta))-beta*H(eta)));
IC[i2] := F(0) = a[i2], (D(F))(0) = 1, (D(F))(L) = epsilon, G(0) = 1, G(L) = 0, H(0) = 1, H(L) = 0;
dsys1[i2] := {Eq1[i2], Eq2[i2], Eq3[i2], IC[i2]};
dsol1[i2] := dsolve(dsys1[i2], numeric, output = listprocedure, range = 0 .. L);
dsol1x[i2] := subs(dsol1[i2], diff(F(eta), eta, eta));
dsol1y[i2] := subs(dsol1[i2], G(eta));
dsol1z[i2] := subs(dsol1[i2], H(eta)) end do;

for j from -L while j <= L do; 
g[j] := eval(-dsol1x[j](0)) end do;
with(plots); 

g6 := pointplot({seq([n/L, g[n]], n = -L .. L)}, symbol = asterisk, symbolsize = 15, color = red);
display(g6);


Please see the problem and correct as soon as possible. I am waiting your positive respone.

Muhammad Usman

School of Mathematical Sciences 
Peking University, Beijing, China

 

Hello! I try to make friends physics package and matrixes. But I am faced with difficulties. To be more specific, to consider a code:

with(Physics):
Setup(mathematicalnotation = true);
Coordinates(X);
Setup(tensors = A[mu](X));
PDEtools:-declare(A(X), p0(X), pm(X), pp(X), pt(X), U(X), m5(X))

And then I create a matrix:

pt := proc (X) options operator, arrow; Matrix(2, 2, [[p0(X), sqrt(2)*pp(X)], [sqrt(2)*pm(X), -p0(X)]]) end proc;

It displays as:

Why do p0, pp, pm become function only one variable x1?

Interestingly that maple understands the next matrix:

Nevertheless even for function only one variable derivative works fine:

And I can construct more complicated functions:

But why is only one variable?

It is well known that fsolve usually increases (internally) Digits in order to obtain the desired accuracy.

But in the following example, it seems that fsolve highly exaggerates :-)   

restart;
N:=40:
Digits:=100:
F:=expand(mul(x-k,k=1..N)):
f:=evalf(F):
S:=[fsolve(f,complex)];

Error, (in fsolve) Digits cannot exceed 38654705646


Note that the bug does not appear if e.g. F:=expand(mul(x-k-I, k=1..N)):

 

 

How to pdeplot Curl(A(x,y,z))=0 in maple

it has A1(x,y,z) , A2(x,y,z) and A3(x,y,z)

 

Hi all,

 

I have a partial differential equation similar to the following:

Equation: f_x(x,y) + f_y(x,y) = f(x,y) + f(x,0),
Boundary value conditions: f(x,10) = f(10,y) = 0.

The solution is that f is identically equal to 0.

 

However, I am having trouble solving this equation in Maple. I type the following:

pde := diff(f(x, y), x)+diff(f(x, y), y) = f(x, y)+f(x, 0);

bv1 := f(x, 10) = 0;

bv2 := f(10, y) = 0;

solution := pdsolve(pde, {bv1, bv2}, numeric, time = x, range = 0 .. 10);

 

When Maple tries to evaluate the last expression, I get the error

Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {f(x, 0)}

 

It seems to have difficulties with the expression "f(x,0)". Is there some trick to typing this in a way that makes Maple interpret it correctly?

 

Edit: I encounter the same problem, when I try to solve the ODE f'(x) = f(x) + f(0), where f(10) = 0.

 

Best regards.

Is there a method to relate groebner bases with monomials ideals

Hello everyone,

For some reason, the rising edge block is not working how it is supposed to.

The component decription is as follows: "

The Rising Edge component triggers a Boolean expression, true, in the output, y, when a rising edge is detected at the input, u.

I am applying a step signal. (red waveform)

and this is the probe's measurement:

Why is it not detecting the rising edge?

Thanks,

John.

I attempt to understand is it possible whether to calculate the next expression by means of mathematica:

where

{,}- anti-communicator;

 a=0,1,2,3;

\tau^{0}-unity matrix; \tau^{i} - Pauli matrix;

and:
 

 

 


 
finally - Levi-Civita symbol; -Hermitian conjugation.

 

Thank you for your kind replies .

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