MapleSim 2016 is here!

MapleSim 2016 provides variety of improvements to streamline the user experience, expand modeling scope, and enhance connectivity with other tools. Here are some highlights:

• Collapsible task panes provide a larger model workspace, so you can see more of your model at once.
• Improved layout ensures the tools you need for your current task are available at your fingertips.
• The expanded Multibody component library now supports contact modeling.
• A new add-on library, the MapleSim Pneumatics Library from Modelon, supports the modeling and simulation of pneumatic systems.
• The MapleSim CAD Toolbox has been extended to support the latest versions of Inventor®, NX®, SOLIDWORKS®, CATIA® V5, Solid Edge®, PTC® Creo Parametric™, and more.
• The MapleSim Connector, which provides connectivity to Simulink®, now supports single precision export of S-functions so you can run your MapleSim models on hardware that only supports single precision.

See What’s New in MapleSim 2016 for more information about these and other improvements.

eithne

MapleSim 2016 is here!

MapleSim 2016 provides variety of improvements to streamline the user experience, expand modeling scope, and enhance connectivity with other tools. Here are some highlights:

• Collapsible task panes provide a larger model workspace, so you can see more of your model at once.
• Improved layout ensures the tools you need for your current task are available at your fingertips.
• The expanded Multibody component library now supports contact modeling.
• A new add-on library, the MapleSim Pneumatics Library from Modelon, supports the modeling and simulation of pneumatic systems.
• The MapleSim CAD Toolbox has been extended to support the latest versions of Inventor®, NX®, SOLIDWORKS®, CATIA® V5, Solid Edge®, PTC® Creo Parametric™, and more.
• The MapleSim Connector, which provides connectivity to Simulink®, now supports single precision export of S-functions so you can run your MapleSim models on hardware that only supports single precision.

See What’s New in MapleSim 2016 for more information about these and other improvements.

eithne

New color schemes for plotting have been added to Maple 2016. They are summarized here. You can also see more details on the plot/colorscheme help pages, which have been reworked (hopefully in a way that makes them more useful to you).

We released a new video a few weeks ago describing one of these features: coloring by value. The worksheet I used for the video is available here: ColorByValueWebinar.mw

The mechanism of transport of the material of the sewing machine M 1022 class: mathematical animation.   BELORUS.mw 

I thought I would share some code for computing sparse matrix products in Maple.  For floating point matrices this is done quickly, but for algebraic datatypes there is a performance problem with the builtin routines, as noted in http://www.mapleprimes.com/questions/205739-How-Do-I-Improve-The-Performance-Of

Download spm.txt

The code is fairly straightforward in that it uses op(1,A) to extract the dimensions and op(2,A) to extract the non-zero elements of a Matrix or Vector, and then loops over those elements.  I included a sparse map function for cases where you want to map a function (like expand) over non-zero elements only.

# sparse matrix vector product
spmv := proc(A::Matrix,V::Vector)
local m,n,Ae,Ve,Vi,R,e;
  n, m := op(1,A);
  if op(1,V) <> m then error "incompatible dimensions"; end if;
  Ae := op(2,A);
  Ve := op(2,V);
  Vi := map2(op,1,Ve);
  R := Vector(n, storage=sparse);
  for e in Ae do
    n, m := op(1,e);
    if member(m, Vi) then R[n] := R[n] + A[n,m]*V[m]; end if;
  end do;
  return R;
end proc:

# sparse matrix product
spmm := proc(A::Matrix, B::Matrix)
local m,n,Ae,Be,Bi,R,l,e,i;
  n, m := op(1,A);
  i, l := op(1,B);
  if i <> m then error "incompatible dimensions"; end if;
  Ae := op(2,A);
  Be := op(2,B);
  R := Matrix(n,l,storage=sparse);
  for i from 1 to l do
    Bi, Be := selectremove(type, Be, (anything,i)=anything);
    Bi := map2(op,[1,1],Bi);
    for e in Ae do
      n, m := op(1,e);
      if member(m, Bi) then R[n,i] := R[n,i] + A[n,m]*B[m,i]; end if;
    end do;
  end do;
  return R;
end proc:

# sparse map
smap := proc(f, A::{Matrix,Vector})
local B, Ae, e;
  if A::Vector then
    B := Vector(op(1,A),storage=sparse):
  else
    B := Matrix(op(1,A),storage=sparse):
  end if;
  Ae := op(2,A);
  for e in Ae do
    B[op(1,e)] := f(op(2,e),args[3..nargs]);
  end do;
  return B;
end proc:

As for how it performs, here is a demo inspired by the original post.

n := 674;
k := 6;

A := Matrix(n,n,storage=sparse):
for i to n do
  for j to k do
    A[i,irem(rand(),n)+1] := randpoly(x):
  end do:
end do:

V := Vector(n):
for i to k do
  V[irem(rand(),n)+1] := randpoly(x):
end do:

C := CodeTools:-Usage( spmv(A,V) ):  # 7ms, 25x faster
CodeTools:-Usage( A.V ):  # 174 ms

B := Matrix(n,n,storage=sparse):
for i to n do
  for j to k do
    B[i,irem(rand(),n)+1] := randpoly(x):
  end do:
end do:

C := CodeTools:-Usage( spmm(A,B) ):  # 2.74 sec, 50x faster
CodeTools:-Usage( A.B ):  # 2.44 min

# expand and collect like terms
C := CodeTools:-Usage( smap(expand, C) ):

eulermac(1/(n*ln(n)^2),n=2..N,1);  #Error
Error, (in SumTools:-DefiniteSum:-ClosedForm) summand is singular in the interval of summation


eulermac(1/(n*ln(n)^2+1),n=2..N,1);  #nonsense

polygon_2_color.mw

Imitation coloring both sides of the polygon in 3d.  We  build a new polygon in parallel with our polygon on a very short distance t. (We need any three points on the polygon plane, do not lie on a straight line.) This place in the program is highlighted in blue.

Paint the polygons are in different colors.

The method of solving underdetermined systems of equations, and universal method for calculating link mechanisms. It is based on the Draghilev’s method for solving systems of nonlinear equations. 
When calculating link mechanisms we can use geometrical relationships to produce their mathematical models without specifying the “input link”. The new method allows us to specify the “input link”, any link of mechanism.

Example.
Three-bar mechanism.  The system of equations linkages in this mechanism is as follows:

f1 := x1^2+(x2+1)^2+(x3-.5)^2-R^2;
f2 := x1-.5*x2+.5*x3;
f3 := (x1-x4)^2+(x2-x5)^2+(x3-x6)^2-19;
f4 := sin(x4)-x5;
f5 := sin(2*x4)-x6;

Coordinates green point x'i', i = 1..3, the coordinates of red point x'i', i = 4..6.
Set of x0'i', i = 1..6 searched arbitrarily, is the solution of the system of equations and is the initial point for the solution of the ODE system. The solution of ODE system is the solution of system of equations linkages for concrete assembly linkage.
Two texts of the program for one mechanism. In one case, the “input link” is the red-green, other case the “input link” is the green-blue.
After the calculation trajectories of points, we can always find the values of other variables, for example, the angles.
Animation displays the kinematics of the mechanism.
MECAN_3_GR_P_bar.mw 
MECAN_3_Red_P_bar.mw

(if to use another color instead of color = "Niagara Dark Orchid", the version of Maple <17)

Method_Mechan_PDF.pdf

The method of solving underdetermined systems of equations, and universal method for calculating link mechanisms. It is based on the Draghilev’s method for solving systems of nonlinear equations. 
When calculating link mechanisms we can use geometrical relationships to produce their mathematical models without specifying the “input link”. The new method allows us to specify the “input link”, any link of mechanism.

Example.
Three-bar mechanism.  The system of equations linkages in this mechanism is as follows:

f1 := x1^2+(x2+1)^2+(x3-.5)^2-R^2;
f2 := x1-.5*x2+.5*x3;
f3 := (x1-x4)^2+(x2-x5)^2+(x3-x6)^2-19;
f4 := sin(x4)-x5;
f5 := sin(2*x4)-x6;

Coordinates green point x'i', i = 1..3, the coordinates of red point x'i', i = 4..6.
Set of x0'i', i = 1..6 searched arbitrarily, is the solution of the system of equations and is the initial point for the solution of the ODE system. The solution of ODE system is the solution of system of equations linkages for concrete assembly linkage.
Two texts of the program for one mechanism. In one case, the “input link” is the red-green, other case the “input link” is the green-blue.
After the calculation trajectories of points, we can always find the values of other variables, for example, the angles.
Animation displays the kinematics of the mechanism.
MECAN_3_GR_P_bar.mw 
MECAN_3_Red_P_bar.mw

(if to use another color instead of color = "Niagara Dark Orchid", the version of Maple <17)

Method_Mechan_PDF.pdf

Disclaimer: This blog post has been contributed by Dr. Nicola Wilkin, Head of Teaching Innovation (Science), College of Engineering and Physical Sciences and Jonathan Watkins from the University of Birmingham Maple T.A. user group*. 

We all know the problem. During the course of a degree, students become experts at solving problems when they are given the sets of equations that they need to solve. As anyone will tell you, the skill they often lack is the ability to produce these sets of equations in the first place. With Maple T.A. it is a fairly trivial task to ask a student to enter the solution to a system of equations and have the system check if they have entered it correctly. I speak with many lecturers who tell me they want to be able to challenge their students, to think further about the concepts. They want them to be able to test if they can provide the governing equations and boundary conditions to a specific problem.

With Maple T.A. we now have access to a math engine that enables us to test whether a student is able to form this system of equations for themselves as well as solve it.

In this post we are going to explore how we can use Maple T.A. to set up this type of question. The example I have chosen is 2D Couette flow. For those of you unfamiliar with this, have a look at this wikipedia page explaining the important details.

In most cases I prefer to use the question designer to create questions. This gives a uniform interface for question design and the most flexibility over layout of the question text presented to the student.

1. On the Questions tab, click New question link and then choose the question designer.
2. For the question title enter "System of equations for Couette Flow".
3. For the question text enter the text
   
   The image below shows laminar flow of a viscous incompressible liquid between two parallel plates.
   
   
   
   What is the system of equations that specifies this system. You can enter them as a comma separated list.
   
   e.g. diff(u(y),y,y)+diff(u(y),y)=0,u(-1)=U,u(h)=0
   
   You then want to insert a Maple graded answer box but we'll do that in a minute after we have discussed the algorithm.
   
   When using the questions designer, you often find answers are longer than width of the answer box. One work around is to change the width of all input boxes in a question using a style tag. Click the source button on the editor and enter the following at the start of the question
   
   <style id="previewTextHidden" type="text/css">
input[type="text"] {width:300px !important}
</style>
   
   Pressing source again will show the result of this change. The input box should now be significantly wider. You may find it useful to know the default width is 186px.
4. Next, we need to add the algorithm for this question. The teacher's answer for this question is the system of equations for the flow in the picture.
   
   $TA="diff(u(y),y,y) = 0, u(0) = 0, u(h) = U";
$sol=maple("dsolve({$TA})");
   
   I always set this to $TA for consitency across my questions. To check there is a solution to this I use a maple call to the dsolve function in Maple, this returns the solution to the provided system of equations. Pressing refresh on next to the algorithm performs these operations and checks the teacher's answer.
   
   The key part of this question is the grading code in the Maple graded answer box. Let's go ahead and add the answer box to the question text. I add it at the end of the text we added in step 3. Click Insert Response area and choose the Maple-graded answer box in the left hand menu. For the answer enter the $TA variable that we defined in the algorithm. For the grading code enter
   
a:=dsolve({$RESPONSE}):
evalb({$sol}={a}) 
   
   This code checks that the students system of equations produces the same solution as the teachers. Asking the question in this way allows a more open ended response for the student.
   
   To finish off make sure the expression type is Maple syntax and Text entry only is selected.
5. Press OK and then Finish on the Question designer screen.

That is the question completed. To preview a working copy of the question, have a look here at the live preview of this question. Enter the system of equations and click How did I do?

I have included a downloadable version of the question that contains the .xml file and image for this question. Click this link to download the file. The question can also be found on the Maple T.A. cloud under "System of equations for Couette Flow".

* Any views or opinions presented are solely those of the author(s) and do not necessarily represent those of the University of Birmingham unless explicitly stated otherwise.

There has been a spate of Questions posted in the past week about computing eigenvalues. Invariably, the Questioners have computed some eigenvalues by applying fsolve to a characteristic polynomial obtained from a floating-point matrix via LinearAlgebra:-Determinant. They are then surprised when various tests show that these eigenvalues are not correct. In the following worksheet, I show that the eigenvalues computed by the fsolve@Determinant method (when applied to a floating-point matrix) are 100% garbage for dense matrices larger than about Digits x Digits. The reason for this is that computing the determinant introduces too much round-off error into the coefficients of the characteristic polynomial. The best way to compute the eigenvalues is to use LinearAlgebra:-Eigenvalues or LinearAlgebra:-Eigenvectors. Furthermore, very accurate results can be obtained without increasing Digits.

Download Eigenvalues.mw

In addition to the Maple 2015.2 and MapleSim 2015.2 updates for Mac, we have just released updates to both Maple and MapleSim for Windows and Linux.

Maple 2015.2a provides a fix for the sum bug reported here.

MapleSim 2015.a provides a variety of interface improvements, and updates to the MapleSim Battery Library and MapleSim CAD Toolbox.

For Mac users, these improvements are included with the Maple 2015.2/MapleSim 2015.2 updates.

All updates are available through the Check for Updates system, and are also available from our website on the downloads section of our website.

eithne

We have just released updates to Maple 2015 and MapleSim 2015 that fix the problems on Mac OS X 10.11 (El Capitan).  If you want to use the new OS, you should update your products.

Updates are available through Check for Updates and from the Downloads section of our website. See Maple 2015.2 and MapleSim 2015.2 for details. MapleSim users, please note that this update also gives you all the new features in MapleSim 2015.2.

If you are using earlier versions of these products, please read the  Maple and MapleSim on Mac OS X 10.11 FAQ for more information about your options.

eithne

I am learning to use maple for my notes preparation for the subject Finite Element Analysis. It is interesting to know that how often we blame maple or computer for the silly mistakes we made in our commands and expect the exact answers. I have used a small file and find it easy to analyse my mistakes fatser. If we make a small mistake in a big file, it not only gives us problem finding our mistakes, it leads to more mistakes in other parts as well. A command working in one document need not necessarily work the same way in other document.

I have made my first document and people will come with suggestions to make appropriate modifications in the various sections to improve my knowledge on maple as well as the subject.

Download FINITE_ELEMENT_ANALYSIS.mw

Ramakrishnan V

rukmini_ramki@hotmail.com

Since we’re almost at the end of the year, I thought it would be interesting to look back at our most popular webinars for academics in 2015. I found that they fell into one of two categories: live streaming webinars featuring Dr. Robert Lopez and Maple how-to tutorials.  (If you missed the live presentation, you can watch the recordings of all these webinars below.)

The first and second most popular webinar were, unsurprisingly, both of the live streaming webinars that featured Dr. Robert Lopez (Emeritus Professor at Rose Hulman Institute of Technology and Maple Fellow at Maplesoft). These webinars were streamed live to an audience and allowed many people to get their first glimpse of the man behind the Clickable Calculus series and Teaching Concepts with Maple:

1.       Eigenpairs Enlivened

In this webinar, Dr. Robert Lopez demonstrates how Maple can enhance the task of teaching the eigenpair concept, and shows how Maple bridges the gap between the concept and the algorithms by which students are expected to practice finding eigenpairs.

2.       Resequencing Concepts and Skills via Maple's Clickable

In this webinar, Dr. Lopez presents examples of what "resequencing" looks like when implemented with Maple's point-and-click syntax-free paradigm. Not only can Maple be used to elucidate the concept, but in addition, it can be used to illustrate and implement the manipulations that ultimately the student must master.

The next three were all brief webinars on how to complete specific tasks in Maple 2015. Just under a dozen of these were created in 2015 and they were all quite popular, but these three stood out above the rest:

3.       Working with Data Sets in Maple

This video walks through examples of working with several types of data in Maple, including visualizing stock and commodity data, forecasting future temperatures using weather data, and analyzing macroeconomic data, such as employment statistics, GDP and other economic indicators.

4.       Custom Color Schemes in Maple

This webinar provides an overview of the colorscheme option for coloring surfaces, curves and collections of points in Maple, including how to color with gradients, according to function value or point position. Examples of how the colorscheme option is used with various commands from the Maple library are also demonstrated.

 5.       Working with Units in Maple

Maple 2015 allows for more fluid and natural interaction with units. This webinar provides an overview of the new unit formatting controls and new Temperature object, and demonstrates how to compute with units and tolerances.

Are there any topics you’d like to see Robert cover in upcoming webinars? Or, any Maple how-to videos you think would be a helpful addition to our library? Let us know in the comments below!

Kim