Maplesoft Blog

The Maplesoft blog contains posts coming from the heart of Maplesoft. Find out what is coming next in the world of Maple, and get the best tips and tricks from the Maple experts.

A few months ago, I needed to prepare for a customer on-site training session. As part of the request for topics to be covered during the training, my contact there wanted to talk about contact! Contact models are important for multi-body systems because it is about the interactions between objects.  An important example of a contact model is a tire component that interacts with the road. In this case, the training topic requested was a more generic question: “how to create contact models in MapleSim”.  There are, of course, lots of examples available within MapleSim that contain contact models already. Two particular examples came to mind: 1) the bouncing ball; and 2) the catapult. However, this being a training session, simply presenting the example models would not accomplish the purpose of the session. So I broadened my scope and turned my attention to the question: “how does one model contact in general?”

Undergraduate engineering and science consists of learning various rules and laws that govern the domains of interest. For me, it was Maxwell’s Equations for electromagnetics, the Navier-Stokes equation for acoustics, the Rayleigh criterion for imaging, the speed of light, et cetera ad nauseam. What is frequently missed or neglected in teaching and in practice is how these rules and limits are simply the boundaries of the game – endpoints on a spectrum of possibilities. That’s why a recent headline caught my attention: “Computers to Get Faster Only for 75 More Years". I find it hard to believe that humans a thousand years from now will be commemorating 2084 as “The Year Computers Stopped Getting Faster”. After reading the research paper from which this headline arose, I was reminded that innovative science doesn’t set limits, it uses them as tools. Since this is precisely what we do in Applications Engineering at Maplesoft, I thought it would be worth looking into a little further.

If you were to stroll into the Application Engineering office at Maplesoft, you might be led to believe that we subsist on nothing but donuts, pizza, chocolate and coffee.  It’s even worse at this time of year when we have many more opportunities to over-consume. I try to have a balanced diet, but there are too many temptations scattered around the office (including candy at the office entrance – our receptionist, Walli, expects me at 3pm each day without fail). It doesn’t help that a virtually limitless supply of donuts are only a three minute drive away.

One of the most common foods prepared at this time of the year, and arguably the most common kitchen disaster, is turkey. 

There are several employees here at Maplesoft (myself included) who are full-fledged foodies:  not only do we enjoy eating good food, but we enjoy preparing it with all our cool kitchen gadgets.  Just as mathies may compare calculators, we compare chef’s knives.  So being a foodie and a mathie, I was quite intrigued when a co-worker sent me an article that found the optimal cooking temperature for a turkey.

For those of you who have had to take on the task of preparing a turkey, you’re probably familiar with this basic rule of thumb (thousands of burnt turkeys must have contributed to this rule): preheat the oven to 400°F, and then cook it for 20 min/lb at 350 °F.  Essentially what this rule means is that the time required to cook a turkey is directly proportional to the mass of the turkey.  We know that this cannot be true because some people who adhere to this rule will have a turkey that is moist and tender, and others will have a turkey that is dry and tough.  If we take more variables into account, like the size of the turkey (l), oven temperature (T), average density (ρ) and thermal conductivity (κ) we can create a function with respect to time . We can now do a bit of dimensional analysis on this to evaluate the accuracy of the traditional rule of thumb.  By using dimensional analysis, we can formulate a relation between a set of known variables, even though we are not sure of the relationship between these variables. The immediate advantage of this procedure is that less experimentation is required to establish a relationship between the variables, allowing us to take given data and see how it will fit with the equations that are created in the analysis.  I won’t go into full detail here, but I’ve created a Maple worksheet that shows the calculations used in the analysis.  The important part comes from the graphs that are generated:

The black dots represent various cooking times of various sizes of birds.  The red line is the old rule of thumb, which you can clearly see is not very reliable.  The green line represents the new rule of thumb which falls in line much better.  So, what is the magical formula that you should use?  Based on the analysis:  where x is in lbs and the resulting time is in minutes.  Now I will be honest, I haven’t put this to the test yet, but I’ll be sure to try it out this Christmas.

Resellers buy products from a manufacturer, and sell to consumers.  They are an important factor in many industries, including the one in which I work.  Maplesoft operates through a network of resellers throughout the world (apart from North America and a few other territories).  Some may suspect I’m somewhat biased in promoting the importance of resellers; I spent seven years working for Adept Scientific, Maplesoft’s partner in the UK.

The largest resellers are based in larger, better developed markets with a strong manufacturing and research base (like Cybernet and Scientific Computers in Japan and Germany).  Conversely, many smaller resellers, like Multi-On and Czech Software First in Mexico and the Czech Republic, operate in markets with significant growth potential.

Although the digital world has provided me with a wonderful career and countless enriching experiences, in my heart I will always have a special passion towards the analog world: vinyl LP’s, multiple print sets of the Encyclopædia Britannica, a manual wind watch, fountain pens, film cameras and a darkroom, and carbureted motorcycles all have privileged spots in my house. With digital equivalents being so much more accurate, faster, convenient, and cheaper, what could possibly be the appeal of these ancient artifacts?

Atomic operations are CPU instructions that are guaranteed to execute in a single CPU cycle. This means that the operation is guaranteed to complete without being interrupted by the actions of another thread. Although this may not sound too exciting, careful programming using these instructions can lead to algorithms and data structures that can be used in parallel without needing locks. Maple currently does not support atomic operations, however they are an interesting tool and are used in the kernel to help improve Maple's parallelism in general.

Dual- and quad-core PCs are now ubiquitous.  While making your operating system a better multi-tasking environment, they’ve had a limited effect on the code that most technical professionals write.  This is largely because of the perceived difficulty of parallel programming.   The evolution , however, of high-level languages that support multi-threading throughout the 90s and beyond, removed the need to manage threads at the low level, allowing engineers to concentrate on what part of the algorithm could be run in parallel.  Given the ever-increasing complexity of systems that have to be simulated, multi-threaded programming can offer significant time savings for many the problems that can be easily parallelized (and for which time-savings of parallelization outweigh the overhead).

It’s a small world, but there are still too many borders.

I’ve recently become a fan of country music.  It amazes and amuses my wife and children, but I find that country music tells stories that contain some very basic truths.

Brad Paisley sings a song named “Welcome to the Future”.  He begins that song by telling his grandfather’s story of being a soldier in the Philippines fighting the Japanese during World...

In this post I'll take a closer look at the ways in which Maple code can be thread unsafe. If you have not already seen my post on Thread Safety, consider reading that post first. As a brief review, a procedure is thread safe if it works correctly when run in parallel.

The most obvious way in which procedures can be thread unsafe is if they share data without synchronizing access (using a Mutex, for example). So how can two threads share data?

There is something profoundly satisfying when something that goes “viral” on the Web has some connection to your life. This happened recently when I and my colleagues were pointed towards a video of some laboratory robots that somehow drew almost a million views on YouTube alone. For an engineer,...

The first professional training course I gave involved a 275 mile late evening drive in a 1 litre European econobox from Letchworth in the UK to a dingy hotel in Alnwick.  I was pretty nervous –some of my delegates were engineers who had been using Mathcad for over ten years, and I was being paid to tell them what they didn’t know.  The following day, after drinking several litres of coffee, I drove another five miles to the training location, only to find that just one delegate had turned up.  Luckily he was just an intern who’d never used Mathcad before – and to him I was an expert.

Those of you who know me know that besides my family I have three great passions:  History, travel and technology.

I have always been an amateur student of history, reading and learning as much as I can.  But reading only gets you so far.  I think it was Mark Twain who said, “You can’t understand a country until you smell it.”  Smell it?  I think by that he meant that you can’t smell a country unless you are there, which is really the only way to begin to truly understand it.  He was right, of course, and travel is the perfect complement to my love of history.

I'd like to start by thanking all those readers who left feedback on my last post. It was good hear that most of you enjoy reading my posts and that they are generally helpful. I would like to encourage you to continue posting feedback, especially questions or comments about anything that I fail to explain sufficiently.

The following is a discussion of the limitations of parallel programming in Maple. These are the issues that we are aware of and are hoping to fix in future releases.

A leading motorcycle manufacturer has been using MapleSim to model their powertrain, and now they want to include a realistic battery model. This would let them choose batteries and accessories (like starters and alternators) that they can simulate under a variety of operating conditions, along with their powertrain model. The company turned to Maplesoft to help with this modeling exercise and I was put on the task. My background is in circuits so I thought this would be a straightforward project. In my mind batteries were just constant voltage sources that eventually ran out of charge. I was able to find several recent research papers on battery models, and I realized their behavior was much more complicated than a simple voltage source.

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