## Statistical procedures?...

For a statistical course I will give next year, I would like to demonstrate the calculation of tetrachoric and polychoric correlations. Furthermore, it would be nice to show the students how the expectation-maximization algorithm works.

Has anyone already programmed this in Maple?

best regards,

Harry

## Multiple plots in maple...

Hello,

I´a currently making a school assigment, but i can´t get maple plots to combine the graphs i plot, when i plot multiple plots. (see picture) (the code is in the bottom of the question)

as you can see the green and yellow grafh won´t combine. I have tried google but couldn´t find any anserws that worked.
Hope someone can help me!
Thanks!

with(plots); with(Plot);
a := plot(4, x = 0 .. .25, color = red, view = [0 .. .25, 0 .. 5]);
b := plot(1/x, x = .25 .. 1.101, color = blue, view = [.25 .. 1.101, 0 .. 5]);
c := plot(-(1/12)*x+1, x = 1.01 .. 6, color = yellow, view = [1.101 .. 6, 0 .. 5]);
d := plot(.5+sqrt(x-5), x = 6 .. 20, color = green, view = [6 .. 20, 0 .. 5]);
e := plot(1.15*sqrt(x-7), x = 7 .. 20, color = pink, view = [7 .. 20, 0 .. 5]);
display(a, b, c, d, e);

## How to plot multiple functions in one plot?...

I want to plot all three "roots" of the polynom I called 'H[i]' for different values of 'V', in the interval k=0.0..1.0, all in the same plot.

How can I do it, both for real and imaginary parts of H[i]?

file1.mw

## problem with plot or display...

with(plots):R := 5; alpha := (1/9)*Pi;
C1 := plot([R*cos(t), R*sin(t), t = 0 .. 2*Pi], color = blue);
A := [R*cos(alpha), R*sin(alpha)]; B := [R*cos(alpha+Pi), R*sin(alpha+Pi)]; AB := plot([A, B], scaling = constrained);
display({AB, C1}, scaling = constrained);# bad drawing

## Weighted statistical series with DataSummary ?...

I’m working on a weighted statistical series.. and I notice a difference in results with the DataSummary command. Any suggestions? Thank you

QuestionDataWeights.mw

## Error, (in unknown) too many levels of recursion...

Hello,

this is my code:

######################

restart;
g(x,y):=min((3+((x-y)^(2))/(10)+(|x+y|)/(sqrt(2))),(-|x-y|+(7)/(sqrt(2))));

q:=0; h(x,y):=Heaviside(g(x,y)-q);

0
(x, y) -> Heaviside(g(x, y))

p := int(int(h(x, y)*exp((-x^2-y^2)*(1/2))/(2*Pi), y = -infinity .. infinity), x = -infinity .. infinity);

Error, (in unknown) too many levels of recursion

######################

I keep having this error message, is this integral impossible to process or is there someting wrong with the code?

## is it possible to use maple on high performance cl...

https://aws.amazon.com/getting-started/projects/deploy-elastic-hpc-cluster/

is it possible to use maple on high performance clusters?

i can only think to use c program to call cmaple with MPI in linux to use high performance clusters.

is there any other official method to do this?

if i upload my maple 2015 version to amazon for this computing, will it used up all license in this first chance of installation leading to that i can not install maple 2015 linux version to other machine?

https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/ConfigWindowsHPC.html#ComputeNode

which virtual machine should i install the maple 12? on one virtual machine or all compute nodes?

how many compute nodes are need to compute dsolve 100,000 systems which may or may not have solution in maple 12?

## pdsolve and laplace PDE on semi-infinite domain...

Hello Maple experts;

I am not able to understand why Maple 2019 can solve Laplace PDE in 2D Catersian on semi-infinite domain, when the infinity is along the Y direction, but not along the X direction, since the solution method is exactly the same.

Here is the code

```restart;

#right one, Maple can not solve
pde := diff(u(x, y), x\$2)+diff(u(x, y), y\$2) = 0:
bc_left_edge := u(0, y) = 0:
bc_bottom_edge:= u(x, 0) = 0:
bc_top_edge:= u(x, 1) = A:
bc:=bc_left_edge ,bc_top_edge,bc_bottom_edge:
sol:=pdsolve([pde, bc],HINT = boundedseries(x = infinity)) assuming x>0,y>0;

#left one, Maple can solve
pde := diff(u(x, y), x\$2)+diff(u(x, y), y\$2) = 0:
bc_left_edge := u(0, y) = 0:
bc_bottom_edge:= u(x, 0) = 0:
bc_right_edge:= u(1, y) = A:
bc:=bc_left_edge ,bc_right_edge,bc_bottom_edge:
sol:=pdsolve([pde, bc],HINT = boundedseries(y = infinity)) assuming x>0,y>0;

```

Here is screen shot.

Maple can solve both cases if I remove the HINT. But the solution it gives is not as simple as using the HINT and contains unknown constants (_C5) that is why I use the HINT.

But the main question is, since both problems are exactly the same, why Maple can solve one and not the other when using the HINT? Is there something I am doing wrong?

Maple 2019 on windows 10 and Physics cloud version 333.

Thank you

## Circle passing through three non-collinear points....

Suggestions for a Maple program entering the coordinates of three points and giving the equation of the circle passing through these three points, non-aligned?
Thank you.

## INTEGRATION USING APPROXIMATEINT...

What is the default subinterval set in approximate int in Student[MultivariateCalculus] package? How can I change the subinterval number. Thank you.

## Draw Graph in Cartesius when matrix and the positi...

Dear all,

How to draw graph when the matrix and the position is given in cartesius coordinate?
For example, I have this matrix and the following coordinate

Matrix(9, 9, [[0, 0, 1, 0, 1, 1, 1, 0, 0], [1, 0, 0, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0], [1, 0, 0, 0, 0, 0, 0, 0, 0], [1, 0, 0, 0, 0, 0, 0, 0, 0], [1, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 1], [0, 0, 0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 1, 0]])

#Coordinate
[40, 40], [22, 22], [36, 26], [21, 45], [45, 35], [55, 20], [55, 45], [26, 59], [55, 65]

For sure, we can use Graph package
GT := GraphTheory;
G := GT:-Graph(X);
GT:-DrawGraph(G):
How to assign the coordinate such that I get the result of drawing in cartesius ?

Thank you anyway

## Exact value for factorial 1/2...

Hi!
which Maple command gives the exact value of factorial (1/2)?   ``(1/2)!``

Thanks.

## pdsolve in Maple 2019 prints internal results to s...

This is a minor issue, but I noticed using Maple 2019, with Physics cloud version 331 that it prints on the screen some results from internal computation on some calls to pdsolve

I have a ":" at the end of each command, so no output should go to the screen. In Maple 2018 this does not happen.

```pde := a*diff(w(x,y),x) +  b*arctan(lambda*y)*diff(w(x,y),y) =  a*arctan(mu*x)^m+arctan(beta*y)^k:
sol := pdsolve(pde,w(x,y)):

#another example

pde := a*diff(w(x,y),x) +  b*arccot(lambda*y)*diff(w(x,y),y) =  a*arccot(mu*x)^m+arccot(beta*y)^k:
sol:=pdsolve(pde,w(x,y)):```

Running the above on Maple 2019 and Maple 2018, here is screen shot. Notice the output in Maple 2019

In Maple 2019

## How can I add error bars to plot in Maple?...

Hello everyone!

I have the following Maple code:

```with(CurveFitting); with(plottools); with(Statistics); A := [[1.364, 0.64765768e-1], [2.05, -.182176113], [2.664, -0.13914542e-1], [2.728, 0.2193938e-1], [4.092, -0.18349139e-1], [4.1, -.312968801], [5.328, -0.1819837e-2], [5.456, -.28840961], [6.15, -.57076866], [7.992, .175022254]];
F := LeastSquares(A, x);
plot([F, A], x = 0 .. 8, legend = ["Метод наименьших квадратов", "Экспериментальные данные"], legendstyle = [font = ["Roman", 15]], labels = ["d, ìì", "ln(I/I_0)"], labelfont = ["Roman", 15], labeldirections = ["horizontal", "vertical"], axesfont = ["ROMAN", "ROMAN", 15], color = [red, blue], style = [line, point], linestyle = [solid], symbolsize = 20, title = "Определение линейного коэффициента поглощения", titlefont = [Roman, bold, 20]);
```

This produces a plot:

How can I add error bars to the points that are colored in blue?

Thank you in advance for any help!

## Symbolic PDE solve with BCs...

Having problems with solving PDE with symbolic BCs.

u(x,y,t,M,A);

M,A,x are constants for this problem.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>Code Starts

pde := diff(u(x, y, t), t)-.5*(diff(u(x, y, t), y, y))-A*sin(M*x-t) = 0

bc[1] := u(x, 0, t) = 0

bc[2] := u(x, 10, t) = A*sin(M*x-t)

sys := [pde, bc[1], bc[2]]

pdsolve(sys)

>>>>>>>>>>>>>>>>Code ends

I don't get any solution after this.
Moreover, in the second BC, I would like to change 10 to inifnity.