Hello,

non-expert Maple user here.  Any help would be appreciated, I am trying to perform the following process:

1) Represent State Space matrices calculated by hand (ex: A, B, C, D) as a Maple object.

2) Find a solution to the State Space system of equations based on given initial conditions, or represent the same in any other form such as a plot or table.  I am right now trying without much success to use the ResponsePlot and Simulate functions for this.

I have completed (1) using the DynamicSystems > StateSpace object of the form

sys:= StateSpace(A,B,C,D)    // where A, B, C, D are the numeric matrices of the typical S-S set.

using a simple constant '1' as an algebraic input test, I use the ResponsePlot as follows:

ResponsePlot(sys, 1) 

Maple gives me the error: 

Error, (in DynamicSystems:-Simulate) for a continuous system, the second argument (input) must be an algebraic expression or a list of algebraic expressions; received Vector(7, [0,1,2,3,4,5,6])
NULL;

I am sure I'm missing something simple.  Can someone please assist in showing me what I'm doing wrong?  I tried using a vector [0,1,2,3,4] instead of an algebraic function, but it still returned an error.  I am open to other ways too, but the next best way seems to be to convert from StateSpace into individual differential equations and then solve them all manually with dsolve.  It seems like there has got to be a simpler way than that.  Does anyone know of a simple way to implement this process?

i did try but i don't know the result is not come out? also i am not sure to put equation in eq1 in pde or linear part?

Download parameters.mw

Can I define the creation and annihilation operator commutation relations with an explicit momentum dependence?

The goal is to implement an expression of a discrete scalar plane-wave solution to the Klein-Gordon equation that makes use of the creation and annihilation operators in the Physics package.

We don't bother solving the Klein-Gordon equation explicitly. Instead, we just take a solution from literature. This approach is sufficient to show the difficulty in defining the the creation and annihilation operators in this way.

how_to_define_creation_and_annihilation_operators_with_a_momentum_dependence.mw

Download how_to_define_creation_and_annihilation_operators_with_a_momentum_dependence.mw

Whenever I have local proc inside a proc, and use local variables from the outer proc inside it, Mint tells me that the variables are not used.

This can't be right. Why does it say that? Here is MWE. I have this foo.mpl file

foo := proc()

local C1;
local y,x;

    proc()
        C1:= `tools/genglobal`(_C); 
        sol:=y(x)=  C1; 
    end proc();

end proc;

We see clearly that C1 is used, also x and y are used. There can be more code using these inside the inner proc. But this is what mint says

"C:\Program Files\Maple 2024\bin.X86_64_WINDOWS\mint.exe" foo.mpl

    |\^/|      Maple 2024 Diagnostic Program
._|\|   |/|_.  Copyright (c) Maplesoft, a division of Waterloo Maple Inc. 2024
 \  MINT   /   All rights reserved. Maple is a trademark of
 <____ ____>   Waterloo Maple Inc.
      |
Procedure foo() on lines 1 to 11
  These local variables were never used:  C1, x, y

Any idea why it says these are not used?

Also, I noticed it did not warn me that variable sol is global inside the proc. i.e. I was expecting something like this 

          These names were used as global names but were not declared: sol

Which is typical message mint gives when using a name inside a proc which was not declared,

Maple 2024.2 on Windows

I have a square matrix of data points. Each point is between 0 to 0.2. I wish to plot it and set the axes to values from 0 to 1. I want the 3D plot to be plotted with a constrained scaling. The two options I have are plots:-matrixplot and plots:-surfdata. 

* matrixplot can constrain the data, but it isn't obvious how to change the axes so that it shows from 0 to 1 in both directions. 

* In surfaceplot, it is easy to adjust the axes values, but scaling=constrained does nothing. 

(I assume someone else might also appreciate the answer. So, instead of me continuing to struggle, I post here and hope someone can answer without the use of many brain cells.) 

Example attached.

Download Scaled_matrix_plot_with_axes.mw

If I understand right, in the following calling an exception should be raised since the return value of the matching coercion procedure is of course not of type “set”: 

restart;
foo := (x::coerce(set, (y::rtable) -> convert(y, list))) -> x:
foo(<0>);
 = 
                              [0]

Did I miss something?

I want to remove the Lambert function (LambertW) from my equation, but I don't know how. I tried using the explicit option, but it didn't work. How can I express the equation without LambertW?

Download remove.mw

How i can add lebel inside graph  like this picture for some graph , in somecoding i have but i can't how it work i want add to  my code but i can't do the same as paper did

label.mw

Hi! A basic issue.

Why view=[-2 ..1, -2 ..5]  is not useful here? According to the output, only the green line meets the view settings. I want to extend the left side of these three lines appropriately (show the intersection)

Download The_intersection_parallelism_and_coincidence_of_two_straight_lines.mw

Hi,

I'm trying to use the Explore command to examine the effect of two parameters (mu and sigma) on the density function curve. The visualization isn't very optimal, especially with the mu parameter, and it's difficult to add options (range, color, gridlines, etc.). Any suggestions to optimize this idea? Thanks for your insights!

Q_Explore.mw

when we have ode equation we say what is type of equation then  i want solve by this method say the name of method and if possible i want to solve this equation by the method step by step too, maple can do that? also can we plot the solution or any geometricall presentation , also i have error in writing exact form of equation

Download ode-example.mw

i want try all number to my parameter for check the shape of plot there is any way for doing that?

Download control-trajectory.mw

THis IC for Abel ode is not valid and should result in no solution. But instead of returning NULL, dsolve throws internal error called Error, (in dsolve) invalid limiting point

Download internal_error_instead_of_no_solution.mw

Is there an equivalent of currentdir() which instead of returning current working directory, returns the directory of the file being read. So assume I have an ".mm" or ".mpl" file saved in some location and there is another file with a location fixed relative to this file, but not fixed in absolute location on the computer and not fixed relative with current working directory. One natural thing is to have a line in the first file that takes its current location (not current working location of the user!) and then use the fixed relative path info, and then gives the location of the second file to the user. Using currendir won't help here because current working directory is not necessarily the same as the location of the file you are reading, the first file. One may say the user is reading the first file so he knows already its location, right? Well, if the user is also the writer of the file, sure, not a problem, he can manually edit the lines of the file and put that location inside the file instead of using currentdir etc. However, if the user is not the writer and also does not know how to edit or whatever else reason, then the file should be able to inform Maple of its own location, so that's why something like currentdir() but not for the working directory, instead for currently being read file's directory is helpful. I checked FileTools package quickly and couldn't notice anything like what I want. Anyone have any clue on name of such command if exists or any other trick that does what I want (except expecting the user to do something ^_^ so all from the writer's side please ^_^).

i try find some part of solution of this kind of pde but i can't get results my openion is maybe this pde is wronge when i defined 

pde.mw