Let us consider the linear integer programming problem:

A := Matrix([[1, 7, 1, 3], [1, 6, 4, 6], [17, 1, 5, 1], [1, 6, 10, 4]]):
 n := 4; z := add(add(A[i, j]*x[i, j], j = 1 .. n), i = 1 .. n):
restr := {seq(add(x[i, j], i = 1 .. n) = 1, j = 1 .. n), seq(add(x[i, j], j = 1 .. n) = 1, i = 1 .. n)}:
 sol := Optimization[LPSolve](z, restr, assume = binary);

Error, (in Optimization:-LPSolve) no feasible integer point found; 
use feasibilitytolerance option to adjust tolerance

sol1 := Optimization[LPSolve](z, restr, assume = binary, feasibilitytolerance = 100, integertolerance = 1);

Error, (in Optimization:-LPSolve) no feasible integer point found;
 use feasibilitytolerance option to adjust tolerance

That was OK in Maple 16, outputting

.

The bug in one of the principal Maple commands lasts since Maple 2015, where the above code causes "Kernel connection has been lost". The SCRs about it were submitted three times (see http://www.mapleprimes.com/questions/204750-Bug-In-LPSolve-In-Maple-20151).

We have just released a small update to MapleSim.  MapleSim 2016.2a is an update to MapleSim 2016.2 that includes improvements in several areas, including corrections to problems related to custom components and importing Modelica libraries. As usual, we recommend that every MapleSim customer install all available updates.  The update is availble through Help>Check for Updates and as a download from our website.  See MapleSim 2016.2a for details.

eithne

The Möbius strip  Mobius_strip_rolling.mw

Variants :


The line and the curve on the surface.

Recently, I came across an addendum to a problem that appears in many calculus texts, an addendum I had never explored. It intrigued me, and I hope it will capture your attention too.

The problem is that of girding the equator of the earth with a belt, then extending by one unit (here, taken as the foot) the radius of the circle so formed. The question is by how much does the circumference of the belt increase. This problem usually appears in the section of the calculus text dealing with linear approximations by the differential. It turns out that the circumference of the enlarged band is 2*Pi ft greater than the original band.

(An alternate version of this has the circumference of the band increased by one foot, with the radius then being increased by 0.16 ft.)

The addendum to the problem then asked how high would the enlarged band be over the surface of the earth if it were lifted at one point and drawn as tight as possible around the equator. At first, I didn't know what to think. Would the height be some surprisingly large number? And how would one go about calculating this height.

It turns out that the enlarged and lifted band would be some 616.67 feet above the surface of the earth! This is significantly larger than the increase in the diameter of the original band. So, the result is a surprise, at least to me.

This is the kind of amusement that retirement affords. I heartily recommend both the amusement and the retirement. The supporting calculations can be found in the attached worksheet: Girding.mw

Let us consider 

restart; 
MultiSeries:-limit(sin(n)/n, n = infinity, complex);
0

The answer is wrong: in view of the Casorati-Weierstrass theorem the limit does not exist. Let us try another limit command of Maple

limit(sin(n)/n, n = infinity, complex);


(lim) (sin(n))/(n)

which fails. Therefore, Maple user does not obtain the correct answer. 

Suppose we have some simple animations. Our goal - to build a more complex animation, combining the original animations in different ways.
We show how to do it on the example of the three animations. The technique is general and can be applied to any number of animations.

Here are the three simple animations:

restart;
with(plots):
A:=animate(plot, [sin(x), x=-Pi..a, color=red, thickness=3], a=-Pi..Pi):
B:=animate(plot, [x^2-1, x=-2..a, thickness=3, color=green], a=-2..2): 
C:=animate(plot, [[4*cos(t),4*sin(t), t=0..a], color=blue, thickness=3], a=0..2*Pi):
 

In Example 1 all three animation executed simultaneously:

display([A, B, C], view=[-4..4,-4..4]);

In Example 2, the same animation performed sequentially. Note that the previous animation disappears completely when the next one begins to execute:

display([A, B, C], insequence);

Below we show how to save the last frame of every previous animation into subsequent animations:

display([A, display(op([1,-1,1],A),B), display(op([1,-1,1],A),op([1,-1,1],B),C)], insequence);

Using this technique, we can anyhow combine the original animations. For example, in the following example at firstly animations  A  and  B  are executed simultaneously, afterwards C is executed:

display([display(A, B), display(op([1,-1,1],A),op([1,-1,1],B),C)], insequence);

The last example in 3D I have taken from here:

restart;
with(plots):
A:=animate(plot3d,[[2*cos(phi),2*sin(phi),z], z =0..a, phi=0..2*Pi, style=surface, color=red], a=0..5):
B:=animate(plot3d,[[(2+6/5*(z-5))*cos(phi), (2+6/5*(z-5))*sin(phi),z], z=5..a, phi=0..2*Pi, style=surface, color=blue], a=5..10):
C:=animate(plot3d,[[8*cos(phi),8*sin(phi),z], z =10..a, phi=0..2*Pi, style=surface, color=green], a=10..20):
display([A, display(op([1,-1,1],A),B), display(op([1,-1,1],A),op([1,-1,1],B),C)], insequence, scaling=constrained, axes=normal);

AA.mw

We have just released an update to Maple.  It includes updates to the Maple Workbook, the video component, the Physics package, and many other small improvements throughout the product. It is available through Tools>Check for Updates in Maple, and is also available from our website on the Maple 2016.2 download page.

eithne

We have just released a major update to MapleSim and the MapleSim family of products. This update includes significant enhancements in the areas of model development and toolchain connectivity, including:

• Live simulations let you see results as the simulation is running, so you can track progress and react to problems immediately.
• A new 3-D overlay option lets you easily compare simulation visualizations by overlaying one visualization on top of another
• Tools for revision control enable a structured approach to managing and tracking changes to your model, making it easier to manage projects when multiple engineers are working on the same model and reducing development risk.
• MapleSim now supports direct import of models created in other FMI-compatible software, providing even greater cross-tool compatibility and opportunities for co-simulation.
• The MapleSim Connector, for connectivity with Simulink®, and the MapleSim Connector for FMI, for exporting MapleSim models to other FMI-compatible tools, have been expanded to allow you to explore simulation results involving exported MapleSim models from within MapleSim, even though the simulation was done in the target tool.

• And more! See What’s New in MapleSim for more information about these and other improvements in MapleSim.

This update is being distributed through the automatic Check for Updates system, and is also available from our website. See the MapleSim 2016.2  downloads page for details on obtaining this update.

eithne

I'd like to pay attention of Maple community to the recent work by Alex Degtyarev in algebraic geometry done with Maple.

Bertini.zip

I am pleased to announce that we have just released a significant update to Maple T.A. 2016, our online assessment system.

Maple T.A. 2016.1 includes a wide range of features and improvements that have been requested by customers, including new options for questions and assignments, improved content management, and enhanced integration with course management systems. It also includes a substantial number of small enhancements and corrections across all areas of the product, providing improved responsiveness, more efficient load handling, and smoother workflow for instructors and students.

For more information, visit What’s New in Maple T.A.

Jonny Zivku
Product Manager, Online Education Products

Custom_Palettes_and_Palette_Entries.mw

Let us consider 

with(Statistics);
U := RandomVariable(DiscreteUniform(-10, 10)):
V := RandomVariable(DiscreteUniform(-10, 10)):
Probability(U^2-V^2 <= 1/9, numeric);
  0.

, whereas a positive number greater than 1/21 is expected. 

Let us consider the example from Maple help to ?ProbabilityFunction (also see ?Geometric)

with(Statistics):
ProbabilityFunction(Geometric(1/3), 5);
                              32 /729
                             

Let us continue the investigation

ProbabilityFunction(Geometric(1/3), 5.1);
0.4215152817e-1
ProbabilityFunction(Geometric(1/3), 5.12);
0.4181109090e-1
ProbabilityFunction(Geometric(1/3), 51/10)
(32/2187)*2^(1/10)*3^(9/10)

whereas the result 0 is expected in all the three cases up to Wiki. I am aware of the line

"t-algebraic; point (assumed to be an integer)"

in the help. However, 

ProbabilityFunction(Geometric(1/3), -.5);
                               0

The same issue with the DiscreteUniform distribution. This bug lasts from  at least Maple 16. The question arises: may we trust Maple?

HI MaplePrimes.com and other watchers,

Please enjoy the attaced files about combinatorics.
You may already know what '4 choose 3' is.

an_excercise_in_combinatorics.mw

an_excercise_in_combinatorics.pdf

Hopefully this can be useful to the casual mathematical observer.

Regards,

Matt

Graphical Programming with MapleSim in Vector Mechanics to Structures 2D

At the present time before constructing or starting to develop a mechanical structures project it is necessary to model it using graphic programming; In this opportunity and used MapleSim as a computational tool belonging to the company Maplesoft. The modern approach to modeling and simulation makes the fabrication of complex designs easy to solve. We will cover some examples taken from the engineering being implemented in Maplesim with insertion of physical objects; To be seen in real time through video output; Then integrates with Maple to analyze the equations and data through the static and dynamic behavior of the fabricated. Solved methods of physical block components include functionality for many domains: rotational and translational mechanics, multi-body dynamics, logic, and structural blocks; With techniques like: Drag-and-Drop Physical Modeling Environment and Create Custom Components Directly From Their Equations, thus the systems that would take hours or days to build from equations; In principle they can be created in a fraction of time using MapleSim, so it can incorporate significantly more complex graphical algorithms. In MapleSim, I use the revolutionary multibody technology that perfectly combines advanced multi-domain modeling tools to provide all the functionality you need in one environment.

FAST_UNT_2017.pdf

Lenin Araujo Castillo

Ambassador Maple - Perú