Samir Khan

1169 Reputation

14 Badges

11 years, 206 days

My role is to help customers better exploit our tools. I’ve worked in selling, supporting and marketing maths and simulation software for all my professional career.

I’m fascinated by the full breadth and range of application of Maple. From financial mathematics and engineering to probability and calculus, I’m always impressed by what our users do with our tools.

However much I strenuously deny it, I’m a geek at heart. My first encounter with Maple was as an undergraduate when I used it to symbolically solve the differential equations that described the heat transfer in a series of stirred tanks. My colleagues brute-forced the problem with a numerical solution in Fortran (but they got the marks because that was the point of the course). I’ve since dramatized the process in a worksheet, and never fail to bore people with the story behind it.

I was born, raised and spent my formative years in England’s second city, Birmingham. I graduated with a degree in Chemical Engineering from The University of Nottingham, and after completing a PhD in Fluid Dynamics at Herriot-Watt University in Edinburgh, I started working for Adept Scientific – Maplesoft’s partner in the UK.

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These are Posts that have been published by Samir Khan

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).

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.

The evolution of written language started in earnest in 3500 BC with Cuneiform, spurring a step-change in the volume of information that could be recorded and transmitted over large distances.

This evolved into wide spectrum of other methods of information transmission. The first transatlantic telegraph cables, for example, were laid in the mid-to-late nineteenth century by information pioneers – industrialists who saw the vast benefit in increasing the rate of information exchange by many orders of magnitude. This led to a Cambrian explosion in the sheer volume of information transmitted internationally, increasing trade and commerce to hitherto unseen levels.

A few mornings ago, I drove to the office, bleary-eyed and still waiting for my first liter of coffee to kick in.  I parked, exited my car, and started walking to the entrance.  Someone a few meters ahead of me held the door open, but let go while I was still about a meter away.  Judging the closing speed of the door, I thought I had enough time to sneak in.  However, during the latter stages of its closing sweep, it suddenly sped up, and slammed shut. Not yet being suitably caffeinated, I uttered a small curse, damning the door and all its close mechanical relatives, and reached for my key fob.

When I was a toddler and learning about the concept of numbers, I used to play a simple game with my parents.  They’d think of a number, and I’d try to guess it.  They would shout “hotter!” if I were getting closer to the number and “colder!” if I was getting further away.  I’m still fascinated by number games, but now it’s Sudoku, the Countdown numbers game… or balancing my bank account at the end of the month.

I spent many of my callow teenage years playing games of chance involving dice and cards.  But it was only after I stopped playing that I stopped losing money. I guess at that time I never really understood the Gambler’s Fallacy, or probability itself.

(Pop quiz: Toss a coin 40 times - what are the chances of getting six heads or six tails in a row? The answer’s in a post script below, together with some Maple code.)

At university, I became fascinated by a UK quiz show called Countdown (and not just because I had a crush on Carol Voderman – an ex-presenter).  In one of the rounds, the contestants have to find the combination of additions, subtractions, multiplications and divisions to make six seed numbers equal a target. 

I’ve attached a Maple worksheet that automatically solves the Countdown numbers game (a simple click of a button asks Maple to find the solution for you).  Kent – one of the sales people I work with – was so fascinated by the worksheet that he spent an entire weekend playing with it, much to the displeasure of his wife and kids. 

Now, if I want some mental stimulation, I often crack open a book of Sudoku puzzles I’ve got lying around. By the time I’m bored, I usually break out Joe Riel’s fantastic Maple-based Sudoku solver.

P.S The following Maple procedure gives the probability of k heads (or k tails) in a row out of n coin tosses.

Many people underestimate the chances of getting 6 heads in a row out of 40 coin tosses, and find it hard to accept it’s as high as 26%.  Given a large enough sample size, the improbable is likely to happen.  How else do you explain the English football team finally having a run of wins?

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