If I am in the Maple debugger, stopped in a routine, how can I navigate between stack frames, such as looking at the variables of the calling function?

"outfrom" is not sufficient for this purpose as that continues execution until return, which would change the variables of the routine I am in, and could potentially take a long time. And more importantly for my particular purpose, the routine I am stopped in is a package's "I found an error" routine which is (deliberately) throwing an exception, so there will not be any return.

I can use where or where? to look at the name of the calling routines. Unfortunately, for the code I am debugging, the calling routine is being dynamically loaded so I do not have a file name for it and I cannot put a persistent breakpoint in it: I need to climb the tree of dynamic calls with their various parameters in order to figure out how the error occured.

This is the second of three blog posts about working with data sets in Maple.

In my previous post, I discussed how to use Maple to access a large number of data sets from Quandl, an online data aggregator. In this post, I’ll focus on exploring built-in data sets in Maple.

Data is being generated at an ever increasing rate. New data is generated every minute, adding to an expanding network of online information. Navigating through this information can be daunting. Simply preparing a tabular data set that collects information from several sources is often a difficult and time consuming effort. For example, even though the example in my previous post only required a couple of lines of Maple code to merge 540 different data sets from various sources, the effort to manually search for and select sources for data took significantly more time.

In an attempt to make the process of finding data easier, Maple’s built-in country data set collects information on country-specific variables including financial and economic data, as well as information on country codes, population, area, and more.

The built-in database for Country data can be accessed programmatically by creating a new DataSets Reference:

CountryData := DataSets:-Reference( "builtin", "country" );

This returns a Reference object, which can be further interrogated. There are several commands that are applicable to a DataSets Reference, including the following exports for the Reference object:

exports( CountryData, static );

The list of available countries in this data set is given using the following:

GetElementNames( CountryData );

The available data for each of these countries can be found using:

GetHeaders( CountryData );

There are many different data sets available for country data, 126 different variables to be exact. Similar to Maple’s DataFrame, the columns of information in the built-in data set can be accessed used the labelled name.

For example, the three-letter country codes for each country can be returned using:

CountryData[.., "3 Letter Country Code"];

The three-letter country code for Denmark is:

CountryData["Denmark", "3 Letter Country Code"];

Built-in data can also be queried in a similar manner to DataFrames. For example, to return the countries with a population density less than 3%:

pop_density := CountryData[ .., "Population Density" ]:

pop_density[ `Population Density` < 3 ];

At this time, Maple’s built-in country data collection contains 126 data sets for 185 countries. When I built the example from my first post, I knew exactly the data sets that I wanted to use and I built a script to collect these into a larger data container. Attempting a similar task using Maple’s built-in data left me with the difficult decision of choosing which data sets to use in my next example.

So rather than choose between these available options, I built a user interface that lets you quickly browse through all of Maple’s collection of built-in data.

Using a couple of tricks that I found in the pages for Programmatic Content Generation, I built the interface pictured above. (I’ll give more details on the method that I used to construct the interface in my next post.)

This interface allows you to select from a list of countries, and visualize up to three variables of the country data with a BubblePlot. Using the preassigned defaults, you can select several countries and then visualize how their overall number of internet users has changed along with their gross domestic product. The BubblePlot visualization also adds a third dimension of information by adjusting the bubble size according to the relative population compared with the other selected countries.

Now you may notice that the list of available data sets is longer than the list of available options in each of the selection boxes. In order to be able to generate BubblePlot animations, I made an arbitrary choice to filter out any of the built-in data sets that were not of type TimeSeries. This is something that could easily be changed in the code. The choice of a BubblePlot could also be updated to be any other type of Statistical visualization with some additional modifications.

You can download a copy of this application here: VisualizingCountryDataSets.mw

You can also interact with it via the MapleCloud: http://maplecloud.maplesoft.com/application.jsp?appId=5743882790764544

I’ll be following up this post with an in-depth post on how I authored the country selector interface using programmatic content generation.

Hi all

Is Ising a package?

for i = 1:12000

%while (1),

% Choose a random value between 0 and 1 for the interaction strength

J = rand()+1e-10;

% Perform a simulation

[M, N, E] = ising2(n_grid, J);

% Records the results

Ms = [Ms M/(n_grid^2)];

Es = [Es E/(n_grid^2)];

Ns = [Ns N];

Js = [Js J];

i = i+1;

Is there an elegant way to plot the region between the surfaces z=-y^2 and z=x^2, only on the domain of the XY-plane bounded by the triangle with vertices (0,0), (1,0) and (1,1)?

I am trying to simplify the square of a parameterized polynomial mod 2. My parameters are intended to be either 0 or 1. How do I accomplish this?

For example:

Download Polynomial_Mod_2.mw

I would like to simplify the squared parameters modulo 2. a[3]^2=a[3], etc.

Any help would be appreciated. Elegant methods even more so!

Regards.

How can i over come convergence error, i am unable to apply approxsoln appropriately and continouation as well. regards

Download ehtasham.mwehtasham.mw

This week I am participating in 19th Ising lectures (see https://drive.google.com/folderview?id=0B0uPwoK-03XgSEZpYWljYnpXN0U&usp=sharing). The Serguei Nechaev's talk inspired me to ask the question:
"How to simulate a random walk on an undirected and unweighted (and, of course, connected) graph
(All the paths from a vertex of degree k have the same probability 1/k.)?"
A Maple procedure to this end is welcome.

I want to create a matrix (B) from entries of other matrices (A) with a helper-function (helper). The helper function is defined such that it returns a certain matrix depending on the index variables. This is necessary because the inner matrices are constructed with another function.

Since the helper-function returns matrices, the big matrix is of datatype=matrix. Unfortunately, creating the big matrix with the correct size and forcing the datatype=float, does not yield the desired result. However, the manual definition using the constructor with a list of matrices does create the desired matrix.

How do I resolve a matrix of matrices?

Note: I know that I could write a convert function that copies the entries to a corresponding matrix, though this seems to be unnecessary effort to me.

This might not be minimal but shows the issue. (Compare and )

MWE_matrix_of_matrices.mw

Since it's not every day we receive submission to the Maple Application Center that have words like "quantum entanglement" (and "teleportation"!) in the title, I thought I'd share this one:

Matrix Representation of Quantum Entangled States: Understanding Bell's Inequality and Teleportation

eithne

Hi guys,

I have written a program in Maple 2016 (Windows 7) made of two parts :

1. An initialization step where a formal system of algebraic equations (some non linear) is built
   Let S(U, P) this system, where U denotes a set of unknowns and P a set of parameters (see step 2 below)
2. An iterative step where this system is solved with respect to U for different values of parameters P
   This loop has to be executed N times for values P₁, ..., P_n, ... of P

I observe that the size of the memory (bottom right of the Maple window) inflates as the value of n increases.

I was able to isolate in the loop corresponding to step 2, the procedure MyProc I wrote which is responsible of this memory inflation.
Now I would like to manage this inflation (typically the memory size grows up to 3 GiB for n about one thousand) because of its very negative effects on the computational time (probably Maple does spend a lot of time in swapping operations).

Suspecting the remember process to be the source of this problem, I tried simple tricks such as

• systematically write   > quantity := 'quantity';   for fome intermediate quantities
• use forget  : for example MyProc contains a call to fsolve and,  after "local" declarations, I inserted  the command  forget(fsolve)   
• in the the loop over n,  I even inserted the command forget(Myproc).

None of these tricks was to some extent efficient to contain the memory inflation.

I suppose it is a very common situation that people who use to develop code are familiar with. So maybe some of you could provide my some advices or move me towards "strategies" or "methodologies" to prevent this situation ?
My purpose here is not to ask you to solve my problem, but rather to ask youy to give me hints to be able to manage such kind of situations by myself.


Maybe this question is unorthodox and doesn't have its place here ?
It that case please let me know.

Thanks In Advance


PS : it would be very difficult for me to provide you the code : if it is a necessary condition for you to help me, just forget it, I will understand

Dear All

Using Lie algebra package in Maple we can easily find nilradical for given abstract algebra, but how we can find all the ideal in lower central series by taking new basis as nilradical itself?

Please see following;

Download [944]_Structure_of_Lie_algebra.mw

Regards

a := 18; b := 2; c := 1; d := 1; f := 1; DEtools[phaseportrait]({diff(x(t), t) = a*x-b*exp(x)*y/(1+exp(x))-f*x*x, diff(y(t), t) = -c*y+b*exp(x)*d*y/(1+exp(x))}, [x(t), y(t)], t = 0 .. 100, {[x(0) = .1, y(0) = 18], [x(0) = .1, y(0) = 27], [x(0) = .2, y(0) = 28], [x(0) = .5, y(0) = 16], [x(0) = .6, y(0) = 14], [x(0) = .7, y(0) = 8], [x(0) = .7, y(0) = 29], [x(0) = 1.0, y(0) = 18], [x(0) = 1.0, y(0) = 22], [x(0) = 1.2, y(0) = 20], [x(0) = 1.5, y(0) = 20], [x(0) = 1.5, y(0) = 24.0], [x(0) = 1.6, y(0) = 26.0], [x(0) = 1.7, y(0) = 28], [x(0) = 1.8, y(0) = 21], [x(0) = 2.0, y(0) = 9], [x(0) = 2.0, y(0) = 28]}, x = 0 .. 2, y = 0 .. 30, dirgrid = [13, 13], stepsize = 0.5e-1, arrows = SLIM, axes = BOXED, thickness = 2)

Is there an elegant way to plot in 3d only the portion of the function f(x,y)=sqrt(25-x^2-y^2) for which 9 <= x^2+y^2 <= 16 ? I'm looking for a nice plot that shows it against the whole sphere with radius 5, so that it's clear which part of the sphere is cut out.

Hi,

It might be very silly question, but i dont know why it is not working out. So here is the question. In the attached maple shhet when i am trying to substitute eta(t)=epsilon*z(t) then it is not making that susbtitution for differential operator. Apart from that when i m collecting epsilon terms then also it not collecting it.quesiton.mw

Regards

Sunit

Dear Community,

I get this message

'EQU' is implicitly declared local to procedure 'Z_DAK_FSOLVE'Problem with procedurefor a procedure, and  cannot go further. How can I avoid it?

Tx for the help in advance,

best regards

Andras

Z_DAK_PROC.mw