What's the correct command to return the number of elements in this command? It returns an expression sequence, but I didn't manage to get anything useful in return.

StringTools:-SearchAll("aba", "abababababababababab")

Greetings All,

This is an application for control theory, specifially using Maple to solve control problems in the area of Interconnection and Damping Assignment Passivity Based Control (IDA-PBC).

- Assuming two variables (iL and Vo), there is a potential function that I am trying to solve for called "Ha".  I have two equations here, and I want to solve for Ha using the pdsolve() command:  

eq1 := diff(Ha(iL, Vo), iL) = rhs(result[1]);
eq2 := diff(Ha(iL, Vo), Vo) = rhs(result[2]);
pdsolve( {eq1, eq2  } );

Once I do this, Maple gives me an expression for Ha that has arbitrary functions in it (I understand where these are coming from).  So far, so good.

--> In order to get help solving for these arbitrary functions, I also want to tell Maple some constraints.  For example:

"the Hessian matrix of Ha must be positive definite"

Is there a way to do this?

with(geometry);
with(LinearAlgebra);
xA := 1;
yA := 0;
xB := 0;
yB := 0;
xC := 0;
yC := 1;
Mat := Matrix(3, 3, [xA, xB, xC, yA, yB, yC, 1, 1, 1]);
Miv := MatrixInverse(Mat);
phi := (x, y) -> Transpose(Multiphy(Miv), <x, y, 1>);
for i to 6 do
    B || i := phi(xA || i, yA || i);
end do;
Error, (in LinearAlgebra:-Transpose) invalid input: too many and/or wrong type of arguments passed to LinearAlgebra:-Transpose; first unused argument is Vector(3, {(1) = xA1, (2) = yA1, (3) = 1})
How to correct this error ? Thank you.

First, I should mention that I am new to Maple. When I try to solve the below system of ODEs

sys_ode := diff(x(t), t) = -x(t)^2/(4*Pi*y(t)*(x(t)^2 + y(t)^2)), diff(y(t), t) = y(t)^2/(4*Pi*x(t)*(x(t)^2 + y(t)^2))

with initial conditions of 

ics := x(0) = 1, y(0) = 1

using the command 

sol_analytic := dsolve([sys_ode, ics])

I receive the below error of 

Error, (in dsolve) numeric exception: division by zero

Any help or guidance to resolve this is greatly appreciated.

Certainly a standard question.

I have an integer n*n matrix A (the entries are explicitly integers; there is no variable -type x- in the matrix). I want the Smith normal form of A, that is A=UDV where U,V are integer matrices with determinant +-1 and D is a diagonal matrix with -eventually- some zero and positive integers d_i s.t. d_i divides d_{i+1}.

"SmithForm()" doesn't work directly (I get rational -non integer- matrices). Maybe it is necessary to declare the matrix A as 'Matrix(integer)' ...
Thank you in advance for your help.

Hello,

In my the script a determinant of a matrix is set equal to 0 and then solved for. This formula has infinite solutions. So i will find the second root with: Student:-Calculus1:-Roots(Y, N = 0 .. limit, numeric) . This gives me several solutions and then i pick the second one as this is the critical buckling load of the column with the current parameters. 

Everytime i change a parameter i need to rerun a part of the script. I would like to generate a table where i define lets say parameter A and B and then run the script to give me value Ncr. then repeat this a 100 times with diferent parameters to see the influence of the parameters. 

Ive been looking around but i am not able to figure this one out. I think something like this should be possible? Thank you very much in advance!

Has anybody been able to get Maple working on macOS Sonoma 14.4. I know it's not supported yet, but I thought there might be someone who has solved the issue with the app crashing immediately after startup.

The overloaded  procedure here test returns based on 2 lists or 3 lists entered. The two list has a mixed input type with a default value. The default value of "a" can cause a problem if an explicit value in not entered for "a" in foo1. I not sure is the mixed input type is adding to the problem.
By changing the order of the procedures the problem is avoidable here. But this just a simple example. When there are 6 or so procedures it can be very difficult to select a correct ordering.

Is there a way around this, apart from don't have default values?

I could experiment with changing the input order in each proc but that would break up some logical input sequences on me.

Download 2024-02-3_Q_Overload_proc_.mw

I don't why the limit is not providing me the answer; What did I do wrong?

Im trying to replicate a shape in maple but everytime i plot it i get a big red block of line and i don't know why.

g := piecewise(0 <= x and x < 33, -50*x + 33*y, 33 <= x and 38.78 < y, (x - 47.94)^2 + (y - 40.55)^2 - 312.36, 58 <= x and x < 100 and 0 <= y and y <= 38.78, 0.5778*x^2 - 66.08774*x - y + 1887.9165);
implicitplot(g, x = 0 .. 80, y = 0 .. 60, scaling = constrained)

Any help is greatly appreciated

I have been able to sucessfully use the WeibullPlot function of the statistics package.

Is there an output option (similar to summarize = true for other regressions) for the (reference=true) intercept of (X) value (eta) with the 0.632 line and and slope (Beta) of the line, r^2, etc.?

Thanks,
Bill

I am trying to plot the following.

it consist of a line and a circle.

if tried doing it as so:

f := x -> piecewise(0 <= x and x <= 1.588125352, (-1)*0.39*x^2 + 1.459*x - y, 1.588125352 <= x and x < 4, (x - 1.81)^2 + (y - 0.42)^2 + (-1)*0.94^2);

implicitplot(f(x), x = 0 .. 3, y = 0 .. 1.5, scaling = constrained);

every time i get this ugly line in the point where the funktion switches and i can't seem to remove it.

I've tried discont = true, but it doesn't seem to work on implicitplots. 

Hello,

I am using the Weibullplot function and have gotten a good plot out.  The issue is the gradations on the subticks per decade.

If I set it to three (3) I get 0.2, 0.3, 0.4 subgrid correctly, but only 0.6, 0.7, 0.8 between ).5 and 1.0.

If I set it to four (4) - I get the reverse.

Is this a log plot issue or a weibullplot function issue with respct to setting the subticks on the 10ths correcty of a decade span?  I look forward to thoughts.

with(Statistics);
XX := RandomVariable(Weibull(1, 0.6));
AA := Sample(XX, 100);

AA is a sample matrix of 100 Weibull distributed data points.

WeibullPlot(AA, reference = false, style = line, gridlines = true, size = [800, 500], axis = [tickmarks = [default, subticks = 4], color = darkgreen])

WeibullPlot.mw

Thanks,
Bill

Hi. i want to select terms with sum of powers equal to 1 and other terms with sum of powers more than 1 for the following equation.

Download problem.mw

 actually i need an algorithm to select linear terms from nonlinear ones(sum of powers equals to more than one) and vice versa.

It is &ndash; that is not rendered.

Maple 2023

For comparision Maple 2022.

Can someone reproduce this? Anything I can do about it (some settings maybe)?

Both session directly after restart of Maple.