Dr. Paulina Chin

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17 years, 16 days
Senior Architect
Waterloo, Ontario, Canada

MaplePrimes Activity

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One issue that often confuses users is local versus global optimization in Maple. I'm just going to give an overview here and will explore specific optimization topics more deeply in future blog entries. Please note that I'm covering only the numeric optimization methods here. I'll leave discussion of the exact methods in Maple to others more knowledgeable about those areas.

The Optimization package is built into Maple and is available to all users. This is primarily...

Question: How do I generate tickmarks in multiples of Pi? The answer has been posted before but this question comes up often enough that it is worth repeating. In Maple 10 and earlier versions, you had to build a custom list of tickmarks, and the only way you could get the Greek pi symbol was to use the Symbol font. In Maple 11, you can use the new 'spacing' structure with the 'tickmarks' option. To get tickmarks in multiples of Pi, use: > plot(sin(x), x=0..8*Pi, tickmarks=[spacing(Pi), default]); To get tickmarks spaced by 2*Pi, replace spacing(Pi) with spacing(2*Pi). To get the tickmarks occuring on the odd multiples of Pi, use spacing(2*Pi, Pi). The second argument is a fixed value from which the other tickmarks are determined.
Well, that last blog entry sure generated a lot of discussion! I'm going to move on to something a bit more fun and less controversial: how to generate a 3-D plot of a polyhedron. There are different ways to do this in Maple, depending on how complicated the polyhedron is and what else you want to do with it. I've uploaded a worksheet with a few simple examples. View 86_PolyhedraExample.mw on MapleNet or Download 86_PolyhedraExample.mw
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I've been asked: how do I include a mathematical expression in a plot caption without having it evaluate? An example is displaying 2(x+y) in the caption without having it appear as 2x+2y. The easiest way to do this is to create an atomic identifier from the expression in the input line. In the 2-D input line, you'll have plot(..., caption=2(x+y)). Select 2(x+y) and right-click to bring up the context menu. Then go to 2-D Math -> Convert To -> Atomic Identifier. This turns the expression into a single name. Note that it is no longer equivalent to the expression 2(x+y), even though it looks exactly like it.
In Maple 11, we added the ability to put captions on a plot. To do this, just use the 'caption' option with any plotting command, in the same way you'd use the 'title' option. These options are described in the plot/options help page. One additional change we made in Maple 11 for these two options is to allow the right-hand-side of the option equation to be a list containing the title or caption, followed by a 'font' suboption. So now you can use title=["my title", font=[times, bold, 20]] instead of having to specify the font separately with the 'titlefont' option. You can also display 2-D math in captions, titles and other text elements in a 2-D plot. To do this, simply use the mathematical expression as the option value: e.g. caption=x^2/2. To combine math with plain text, wrap everything in a 'typeset' structure: caption=typeset("my plot of ", x^2/2). If you enter the plotting command in 2-D math, you can use the palettes to build the expression directly in the command.
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