Dear Community,

I have two measured series - time series actually, stored in Excel:

• gas flow (ordered in ascending date order),
• pressure measurements (unordered, more or less randomly distributed dates),

I would like to:

• import the two series into Maple,
• convert them to time series,
• merge them in a way, that the unordered pressure dates are plugged into the ordered gas flow dates, so I finally get a single, ordered date sequence of ascending order.
• pressure and gas flow rates should remain separated of course, i.e. not merged (they should appear in two separate vectors, or matrix columns, whatever)
• if pressure dates and gas flow dates are the same, they should naturally be in the same row, i.e. belong to the same date.

No problems with the import, but I'm lost with the time series handling. I tried to figure it out from the help, but frankly the description is rather difficult, and I also haven't found appropriate examples. Is it possible to do it with Maple's time series feature at all, or something other is more practical? Files and my initial trial are attached.

tx in advance

best regards

Andras

Time_Series_Data.xlsx

TimeSeriesTest.mw

Let say I have an array

A := Array([[1], [2], [3]])
Normally if I would like to extend it I will write, eg:

Extend(A, [[4], [5]])

But because this is not 1D array Maple will rise an error. Is there a way to go over this limitation?

Dear all,

I would like to evaluate mathematical quantities involving 3F2. The function hypergeom in Maple is most probably the so called ordinary hypergeometric function commonly denoted as 2F1.

I was wondering whether 3F2 has already been implemented in Maple. Thank you.

Hello people in mapleprimes,

To the following expression, I want to apply applyop so that I want to change its denominator expanded ,

but I don't know how to do it.

So, I am writing now hoping someone  teach me it.

m:= 2*p/(p^2+1)^2;

op(m) brings the result of 2, p, 1/(p^2+1)^2,

And, op(1,m) is 2, op(2,m) is p and op(3,m) is 1/(p^2+1)^2, and

op([3,1],m) is p^2+1 and op([3,2],m) is -2.

So, the tree is `*`{2,p, 1/(p^2+1)^2}, and the tree of 1/(p^2+1)^2 is `^`{p^2+1,-2}.

And, the command expand can't play that rule on 1/{(p^2+1)^2} as its original rule is

to expand the mere numerator. And, anyway, 1/{(p^2+1)^2} is interpleted by maple as (p^2+1)^(-2),

which is not 1 devided by (p^2+1)^2, the latter of which is seen to be expanded to be p^4+2*p^2+1, but

the interpletation by maple of it is not so, and if applyop(`denom`,expand,m) works, even it is good.

But, it doesn't follow the syntax of maple. Then, can't use applyop in this case?

Best wishes.

taro

hi.

i have problem with this eq.

i need your help.

Cant plot this graph. pls help

Noah-Kazeem_real_tetta_graph.mw

Hello,

I'm stuck with maple 2016 as it crashes after a few minutes use.

it did work for a few weeks. It appears that its java crashing,

ive been given no error code or anything. uninstalling java and reinstaling did work.

im running the proper bit version. (64) rollio

tried backrolling windows, didnt work.

tried running it as Administrator no luck, ran it on backward compatibility windows 8 and 7. 

ive run out of ideas the last option seems to be a clean windows install.

any help would be greatly appreciated.

the laptop in question (HP notebook 15-ba005no)

runs windows 10 (64bit)

8gigs of ram

cpu AMD E2-7110 1.8 GHz

128 GB SSD

gpu amd radeon r2

thanks in advance. 

dkdwarf.

Hello,

I've got the following problem: Sometimes when I let Maple compute an integral it gives a result which is much smaller than it should be. This happens even for rather simple integrals such as the product of a Gauss function and a 1/x-type function. Here's a minimal working example:

restart;
with(plots):
f := x -> exp(-x^2):
g := (x,a) -> 1/(1+abs(x-a)):
plot([f(x),g(x,3)],x=-3..10):
for a from 1 to 100 do
A[a] := int(f(x)*g(x,a),x=-infinity..a-1)
end do:
B:=[seq(A[a],a=1..100)]:
X:=[seq(a,a=1..100)]:
plot(X,B);

The plot it returns looks like this:

which is clearly wrong between around a=35 and a=60...

Does anyone have an idea how this can be repaired?

Hello,

I try to use the Explore function on a trigonometric expressions depending of 8 parameters. My aim is to study the influence of these parameters on the results.

However, i receive an error message and I didn't manage to troubleshoot it.

May you have a look of an extract of my code and see if you see the mistake ?

TestExplore.mw

Thanks a lot for your help.

Dear sir

I try the below program and it is not executing because of error and that error is " unable to match delimiters" 

Please can you varify it.

sol1 := dsolve([diff(diff(diff(f(eta),eta),eta),eta)+f(eta)*diff(diff(f(eta),eta),eta)+((2*n)/((n+1)))*(1-diff(f(eta),eta)^2) = 0, 1/(Pr) *diff(diff(theta(eta),eta),eta)+f(eta)*diff(theta(eta),eta)-((2*p)/((n+1)))diff(f(eta),eta)*theta(eta) = 0, f(0) = 0, D(f)(0) = 1+lambda*'@@'(D,2)(f)(0), D(f)(10) = 1, theta(0)=0, theta(0)=1+sigma*D(theta(0)),theta(10)=1], numeric, method = bvp);  plots[odeplot](sol1, [eta, `@@`(D,2)(f)(eta)], color = red,axes=boxed);

Dear Community,

Is there an explicit command to remove rows or columns from a DataFrame? I've only found the Append command. What's the easiest way to do it?

Tx in advance,

best regards

Andras

eq2 := -4*A[2]*cos(2*x)-16*A[4]*cos(4*x)-36*A[6]*cos(6*x)-64*A[8]*cos(8*x)+a*A[0]+cos(8*x)*a*A[8]+cos(6*x)*a*A[6]+cos(4*x)*a*A[4]+2*cos(2*x)*q*A[0]+cos(2*x)*a*A[2]+q*A[8]*cos(6*x)+q*A[8]*cos(10*x)+q*A[6]*cos(4*x)+q*A[6]*cos(8*x)+q*A[4]*cos(2*x)+q*A[4]*cos(6*x)+q*A[2]*cos(4*x)+q*A[2]

How to extract the co-fficent that do not have cos in it like

a*A[0]+q*A[2]

Dear all

I have a PDE and its analytical solution. I want to find the numerical solution by Finite Difference Method.

I duscratize the PDE and boundary condition and Could not able to solve them togethe.

Here is the file FEM-Nu.mw

of the implicit function sin(x+y)+sin(x) = y at x = Pi , y=0 of order 15? Here is one of the difficulties

restart; eval(implicitdiff(sin(x+y)+sin(x) = y, y, x$15), [x = Pi, y = 0]);
Error, (in expand/bigprod) Maple was unable to allocate enough memory to complete this computation. Please see ?alloc

Hi everybody,

I solve an ODE system numerically with the command

Tend := ….. :
sol := dsolve(MySys, numeric, method=rosenbrock, range=0..Tend):    # or rkf45

One of my colleagues wants the solution in array form for using it in a spreadsheet (namely Excel). 
Here is an example of what I do :
 
data := plottools:-getdata( plots:-odeplot(sol, […..], 0..Tend, refine = Q) ):  # Q rational
result := data[3]:
ExcelTools:-Export (result, …)

To understand the following, you need to know that the time step varies by several decades (at least 3 or 4). and that  numfun is typically in the order of 10^5
 
When I ask Maple to construct  data , Maple seems to sample the solution solaccording to the local time step dsolve has selected (and probably some other parameters ?)
Because this time step varies in very large proportions, the result is sometimes a concentration of points in regions where the solution is rapidly changing (which is desirable) … with some lacunarity in slow varying regions.

To obviate this, sometimes  poor appearance, I used to force Maple to compute the solution by regularly sampling the range ]0, Tend[  and combining this array with the original one (result).
But this not satisfactory for I do not avoid lacunarity region (unless I proceed in some ad hoc way)

Here is my question :
Could you give me some elements about  the way odeplot adapts its sampling strategy according to the local time step, the budget N (the Q value I guess) and maybe numfun ?

Thank you in advance