Hello,

I am having some trouble with the "Seq" command of the "Threads" package. This is a parallel implementation of the usual "seq" command.

I namely defined a (very long) procedure "f" which defines a (very complicated) function $f: R^2 -> R$, taking as arguments an $x$ and a $y$ and returning $f(x,y)$. I want to plot its graph in 3D, which I try to do by making a 3D data structure consisting of points making up the $x$ range, $y$ range, and the evaluations $f(x,y)$. I then want to plot it with the "SurfacePlot" command from the "Statistics" package.

If I define my data structure as

 data := [seq([seq([i/10, j/10, f(i/10, j/10)], i = 1 .. 10)], j = 1 .. 10)]

the SurfacePlot(data) works. However, it is very slow because it runs in serial and the function evaluation "f(x,y)" takes a long time to compute.

I therefore wanted to compute the data in parallel. For this, I use

 data := [Seq([Seq([i/10, j/10, f(i/10, j/10)], i = 1 .. 10)], j = 1 .. 10)]

Sometimes this works, but often it does not and I get the following error after a number of datapoints have been computed (i.e. after evaluations of f have been made).

Error, (in simplify/float) invalid arguments for Float constructor

This is the first time I use parallel computing, so I am not familiar with potential problems that could trigger errors and don't understand very well how parallel computing works. Does "Seq" only compute the different data points [x,y,f(x,y)] in parallel, or does it compute stuff within the procedure "f" also in parallel when evaluating "f(x,y)" at some fixed arguments "(x,y)"? Because another procedure is defined within "f" and it is called multiple times within one "f" call, so in that case it could be a problem with lexical scope. Any suggestion to help me understand and correct my error would be greatly appreciated.

A few days ago my Windows 10 (32 bit) operating system did an update of my Excel 2016. Since that moment I get following message:

However the addin toolbar is still present and WMIMPLEX.xla file is also still present. Removing and reinstalling the addin did not help. So I am wondering what other solutions could be done.

Aside of this I would like to ask some help for the correct syntax in Thermodynamics package calculating water vapor pressure. For one or another reason I do not succeed to find the correct syntax to obtain the water vapor pressure at 24°C.

Thank you in advance for any help

From a tweet by Tamás Görbe : plotting Chebyshev polynomials in polar coordinates leads to some interesting pictures.  Screenshot here, link to the worksheet (and some perhaps interesting puzzles) at the end.

ChebyshevRose.mw

Hi,

I want to add a  degree symbol (°) in my  plot Triangle 2 ( for example 100°  )

Ideas ?

Thanks

QuestionTypeset.mw

Dear Useres!

Hope everyone is fine here! I want to compare the coeficient of exp(k*eta[3]+m*eta[1]+n*eta[2]) for k=0,1,2,3,...,N,n=0,1,2,3,...,N and m=0,1,2,3,...,N for N=10 in the following attached file. But I got some error, please have a look and try to fix it as early as possible. Please take care and thanks

Compare_coeff.mw

This is a just a general type question. Often reading questions posted to do with modules and packages I see "foo" used. I have put together some simple packages for routines I find useful. I am week in general programming knowledge. I would like to know is "foo" something special or a generic name used for testing? Is is an acronym? ...

hello how do i use bracekt for several lines, like in this picture I need to write this in maple.

i already know how to setup matrices for nX1 or 1Xn (as in vector) or multiples such as

nXn (square matrice) or nXm (a none square matrice)

I also know that we have this premade "sketch"

but I need for several line and some times I need on the right side and some time I need on the left side.

but rarely on both sides (and if I need on both side I will just use a matrice)

can you help me

thx

regards OrbitA

Hello, i stumbled across a function that does not want to plot regularly.

The translation: The tension U(t) (in volts) measured across a resistance in a electric circuit is given by U(t)=cos(2t)*U*e^t/10.

a. Plot the graph of y=U(t)
b.Calculate the limit t->infinity and acquire the horizontal asymtote of the graph of y=U(t). 
c. Calculate the intersecting points of the graph of U with horizontal asymptote (dont ask me how, while how can a function intersect with its own asymptotes??). 

So the question actually is how to graph this function?
Maybe then i can make up from that how the function intersects with its own asymptotes.

Thank you!

Greetings,

The Function.  

Download Question_for_maple_primes_4.mw

Hi,

This is my first post here and I am really hoping someone can help me. I just started using Maple and I am using Maple 2021.

I generated numbers using a SEQUENCE and the sequence is called y. I am trying to extract the element (y[n]) and the index (n) of that element based on the CONDITION that y[n] has to lie in between 0 and 1 exclusive (so the element of the sequence or y[n] has to be such that 0 < y[n] < 1). How can I achieve this using select commad and also using a LOOP. Are there any other methods that can be used to achive this result. Any or all help would be really appreciated.

Thank you all.

I have piecewise functon:

k := piecewise(t < t1, kmax, t1 <= t, -kmax, 2*t1 + sqrt(2)*t1 <= t, kmax, 3*t1 + 2*sqrt(2)*t1 <= t, -kmax, 4*t1 + 2*sqrt(2)*t1 <= t, 0)

Everything is a constant except time t. 

I need to Integrate it 4 times. 

sol := int(k, [t = 0 .. t, t = 0 .. t, t = 0 .. t, t = 0 .. t])

I only get result for the first two conditions from the piecewise functon (t < t1, kmax, t1 <= t, -kmax)

I need the result for complete piecewise functon. Also converting to Heaviside doesn't work. I am a complete math moron. Ty

Hi,

I have made a maple file that is meant to test Maple's solution to the nonlinear pendulum equation.  I am doubtful that Maple is finding the correct solution.  Could someone comment on my analysis?

test_nonlinear_pendulum_solution.mw

As I upgraded to Maple 2021 I quickly noticed the missing text format bar. I've looked into the view tabs and done a bit of search, but I can't figure out how to get it back. I mostly use document mode, so I miss it dearly.

Thank you in advance.

Am calculating using the binomial function, and want to plot the output values. So, need to create a vector and plot the values.

Here is the loop,

x := RandomVariable(Binomial(45, 0.9));
for i from 0 to 45 do
    ProbabilityFunction(x, i);
end do;

Cannot seem to find a way to get the output into a list or vector, and then implement the dataplot function .

Many thanks in advance....

Dear Sir/Madam

I want to use explore commad in order to make a plot along with calculating another expression,simultaneously.

The following command does not give the desired result:

Explore([plot(a*x^2+b*x^3,x=-2..2),evalf(a^2+b^2)],parameters = [a = -1.00..1.00, b=-1.00..1.00],placement=right );

I want to have a diagram which depends on both "a" and "b" together with evaluation of the expression "a^2+b^2" somewhere near the control markers.

I appreciate if any one could help.

Thank you very much

I am interested in the inner workings of SignalProcessing:-Convolution. I know I can list it with a higher setting of verboseproc:

with(SignalProcessing);
interface(verboseproc=3); # actually, 2 is enough here...
eval(Convolution);

and get

Obviously the real work happens in IPP:-Convolution, but that seems unknown. How can I list that??

TIA,

Mac Dude

Convolution.mw