## How can Maple calculate this Moment of Inertia...

I am trying to duplicate the answer to a problem of the nutation of a spinning top. The problem is number 6.1.3 in the book Computer Algebra Recipes for Classical Mechanics by Richard Ens and George McGuire.

TopSC := <,>(5*sin(z)*exp(-(Pi-z)/(1.5)), 0, z) for z = 0..Pi

Spacecurve TopSC, when rotated about the z axis, generates the surface of revolution of the top.

The solution requires knowing the moments of inertia (MI) of the top about the z axis and the x or y axis.

Does the following integral correctly calculate the MI about the z axis?

int(2*Pi*TopSC[1]*(TopSC[1]^2), [z = 0 .. z, z = 0 .. Pi])

What sequence of Maple 2016 commands will calculate the top's MI about the x or y axis?

## Logic[Tautology] : differences of behaviour betwee...

Hi everybody,

For at least one function (I haven’t done extensive testing), the package Logic behaves differently in Maple 2015.0 and maple 2016.0

Maple 2015.0 :
Logic:-Tautology(true);
true

Maple 2016.0
Logic:-Tautology(true);
Error, (in sprint) integer expected for integer format   ????     (??? are mine)

For information :
1)  Logic:-Contradiction(true) retruns false for both 2015.0 and 2016.0
2) OS : Windows 7

Is there some modification of the “Logic” package that  I have  missed ?

## Plot one contour of vector field in 3D...

I have some vector field defined on real coordinate space of 3 dimensions (R3). For example:

I want to plot this vector field in 3D (with Cartesian coordinates), but only in one z contour (for example z=0).

Can somebody help me what is the right command to do this?

## Adding a term, then subtracting the term....

Hello people in mapleprimes,

I have an equation called aa in the following.

alias(&delta;x=dx, &Delta;x=Dx,&Delta;y=Dy,&Delta;z=Dz):
aa:=Dz=f(x+Dx,y+Dy)-f(x,y);

As for modification of this expression, I ask your favor to teach me.

Then, I want to change this aa to D[1](f)(x+theta__1*Dx,y+Dy)*Dx+D[2](f)(x,y+theta__2*Dy)*Dy.

But, to do so, I have to split aa into the one including -f(x,y+Dy)+f(x,y+Dy) between two terms

of aa.

But, as maple cancels these terms, I can't do so. How can I insert two terms, then

obtain the expression  D[1](f)(x+theta__1*Dx,y+Dy)*Dx+D[2](f)(x,y+theta__2*Dy)*Dy?

taro

## %Zm format: How is it used with GUI and DocumentTo...

I've read the help page ?printf for the format codes many times over the years. I think that this is new:

The Z modifier, "%Zm" can be used to generate an alternate equivalent dotm representation that is used in communication with the GUI and in DocumentTools related functionality for the creation of XML content for .mw files.

Could someone show me an example of that?

## Maple Evaluating More Than 12 hrs...

Hello, I run Maple to solve Binary Integer Programming problem which contain about 1340 constraint and its goal to maximize the objective function.

At first, it's running for 2 hours and said that the iteration limit was reached. So I try to add 'iterationlimit' at LPSolve opts and set it to 10000, but after 3 or 4 hours it said that the iteration limit was reached. So I set 'iterationlimit' to 100000000 and now Maple keep evaluating more than 12 hours.

I run Maple at my notebook with these spesification:

Processor: Intel Corei3-5005U 2.0 GHz

Memory: 4GB RAM

Windows 10

It is normal? Or I must run Maple in higher notebook spesification?

Below is my Maple file, hope you can help me.

ISL_2017_FASE3.mw

## How to avoid auto simplification in LateX code gen...

How can I get the equation G1 automatically shown in Latex as stated? Example:

G1 := V = Pi*(d/2)^2*h;

latex(G1);

# yields V=1/4\,\pi\,{d}^{2}h

rendered:

How can I make G1 inert so that Latex generator accepts it as input?

## Export Maple worksheet as .txt without extra symbo...

I have data matrix in text file.

I opened it with Maple and replaced decimal commas to decimal points + replaced column separator to semicolon.

Then I set 'Convert to plain text'.

After these modifications, I would like to export that Maple worksheet back to .txt  file with content exactly as shown on the display.

But if I export the worksheet as Maple text, extra pound signs are added to the beginning of each row. In this case I cannot import data to matrix datatype=float.

If I export the worksheet as Plain text, all the rows are destroyed and I cannot import data into matrix as well.

How can I export worksheet content, exactly as shown on display, into text file?

## How to extract two or three columns from an XLSM f...

I attempt to get two (or better, three) datas from an XLSM file. The tools doesn't work. I want then to do some tests about the apparied datas extracted.

Could you help me ? The best I did was getting a matrix result from an XLS (and not XLSM) file, and I don't know what to do with this kind of result, as I want only test some hypothesis as a linear regression with or without least squares, not do learn what to do with this matrix result..

Thx to you,

Milos

## Overlapping subsections in worksheet...

The problem that I'm asking about here doesn't show in the MaplePrimes display of the worksheet below; you'll need to download the worksheet to see it. The problem is that the last subsection (which is currently empty) overlaps with the second-to-last subsection. It also overlapped when it was not empty. I just want to delete that last subsection, but nothing that I've tried works. This is not the first time that I've had overlapping subsections, but previously I've always been able to fix the problem by closing and re-opening the worksheet. That doesn't work in this case.

ReparamT.mw: A scratch space for testing NewSLO:-reparam

Modify at will.

Created by Carl 2016Jun17.

Important: If any change is made to KB.mpl or NewSLO.mpl then before running this worksheet

1. Restart all open Maple sessions.

2. From the command line, run "cmaple -q < update-archive.mpl".

restart;

dir:= "C:/cygwin64/home/owner/hakaru/maple/":

with(NewSLO);

with(KB);

 Passed cases

Cases being worked on

infolevel[reparam]:= 2:

 Linear fractional transformation (LFT) with symbolic coefficients
 LFT with explicit coefficients
 Simplest nonlinear LFT: 1/x
 Symbolic constant multiple
 Two-variable LFT with Gamma
 Two-variable constant multiple with ChiSquare and Standard Normal
 (t16) Sum of std normals to Normal(0, sqrt(2))
 (t20) Sum of n Bernoullis to Binomial
 (t23) Sum of Exponentials to Gamma

## limit of multivariate function...

Hello people in mapleprimes,

I have a question. I hope someone give an answer to me.

rho:=sqrt((x-a)^2+(y-b)^2);

limit(x-a+y-2,rho=0);

brings an error

Error, invalid input: limit expects its 2nd argument, p, to be of type Or(name = algebraic, set(name = algebraic)), but received ((x-a)^2+(y-b)^2)^(1/2) = 0

Isn't other way than the following?

limit(x-a+y-2,{x=a,y=b});

Best wishes.

taro

## What is the best way to return an array in an exte...

I'm trying to call a C function which returns an array. The example on the help page http://www.maplesoft.com/support/help/maple/view.aspx?path=examples/ExternalCalling is to pass in an array with known dimensions, which will be updated in the C function, but I wonder if this is the only way to do it. For example if I have an array of unknown dimensions beforehand, what is the best approach to return this array?

Thanks!

## Aggregate Statistics on DataFrames

by: Maple 2016

Aggregate statistics are calculated by splitting the rows of a DataFrame by each factor in a given column into subsets and computing summary statistics for each of these subsets.

The following is a short example of how the Aggregate command is used to compute aggregate statistics for a DataFrame with housing data:

To begin, we construct a DataFrame with housing data: The first column has number of bedrooms, the second has the area in square feet, the third has price.

bedrooms := <3, 4, 2, 4, 3, 2, 2, 3, 4, 4, 2, 4, 4, 3, 3>:area := <1130, 1123, 1049, 1527, 907, 580, 878, 1075,          1040, 1295, 1100, 995, 908, 853, 856>:price := <114700, 125200, 81600, 127400, 88500, 59500, 96500, 113300,           104400, 136600, 80100, 128000, 115700, 94700, 89400>:HouseSalesData := DataFrame([bedrooms, area, price], columns = [Bedrooms, Area, Price]);

Note that the Bedrooms column has three distinct levels: 2, 3, and 4.

convert(HouseSalesData[Bedrooms], set);

The following returns the mean of all other columns for each distinct level in the column, Bedrooms:

Aggregate(HouseSalesData, Bedrooms);

Adding the columns option controls which columns are returned.

Aggregate(HouseSalesData, Bedrooms, columns = [Price])

Additionally, the tally option returns a tally for each of the levels.

Aggregate(HouseSalesData, Bedrooms, tally)

The function option allows for the specification of any command that can be applied to a DataSeries. For example, the Statistics:-Median command computes the median for each of the levels of Bedrooms.

Aggregate(HouseSalesData, Bedrooms, function = Statistics:-Median);

By default, Aggregate uses the SplitByColumn command to creates a separate sub-DataFrame for every discrete level in the column given by bycolumn.

with(Statistics);
ByRooms := SplitByColumn(HouseSalesData, Bedrooms);

We can create box plots of the price for subgroups of sales defined by number of bedrooms.

BoxPlot( map( (m)->m[Price], ByRooms),              deciles=false,              datasetlabels=["2 bdrms", "3 bdrms", "4 bdrms"],              color=["Red", "Purple", "Blue"]);

I have recorded a short video that walks through this example here: https://youtu.be/e0pqCMyO3ks

## How to use seq to make a sequence of functions?...

When using seq function below in the second call, it does not generate a sequence of functions with 'a' being 1, 2, and 3, and I had expected.

First seq function call is just to show that it works without the function "x ->" wrapping.

I could of couse use unapply as in the third call, but I had expected the second call to work.

Am I doing anything wrong, or is this a Maple bug?

## Notation of diff and ' that is diff(f(x),x) and f'...

#Hello people in Mapleprimes,

#After

restart;interface(typesetting=extended);

diff(f(x),x);

#shows f'(x).

#But,

diff(f(t1),t1);

#shows just df(t1)/dt1, not f'(t).

#Can't I show f'(t1) not df(t1)/dt1?

#Is this a way peculiar to Maple?

#I hope someone could give me some hints.

#Best wishes.

#taro

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