Dr. David Harrington

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17 years, 356 days
University of Victoria
Professor or university staff
Victoria, British Columbia, Canada

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I am a professor of chemistry at the University of Victoria, BC, Canada, where my research areas are electrochemistry and surface science. I have been a user of Maple since about 1990.

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These are replies submitted by dharr

Since the splines are separate between each data point, I don't think there is a shortcut. But the numeric DE solver has an interpolant scheme and the derivatives up to one less that the order of the DE are already available because they are generated as part of solving the DE. If you want the highest order derivative, you can just solve an artificially higher order DE.

Suggest you upload your worksheet with the big green up arrow, so we can take a closer look.

@janhardo I could have finished it with the geometry package (FindAngle GCH, then get the area of the circular sector and subtract the area of the triangle GCD, and similarly with the other circle). For each object you can ask for details and get equations of lines, coordinates etc. So it probably can do the same things, though I have no experience with Geometry Expression. My general impression is that the geometry package is quite fussy about not doing things that might not be strictly correct, and needs appropriate combinations of assumptions - but Maple's assume facility is not always up to the task.

@Reshu Gupta  This code runs without error in Maple 2017

@DarkMath I'm guessing this has to do with the capabilities of solve. solve(x^2-9) gives 3,-3 but solve(sin(x)) is lazy and gives only 0. solve(sin(x),allsolutions) gives Pi*_Z1 with about (_Z1) showing _Z1 is an integer. So that could be used with some additional range checking. But solve(sin(x),useassumptions) assuming x>-3*Pi/2,x<3*Pi/2; returns only zero.

Maple's Dirac help page certainly suggests it uses the rule you specfied, so I think it is not unreasonable to expect Maple to do better in this case.

@vs140580  Not really your question, but perhaps the Iterator package does what you want, esp Iterator:-permute.

When I run the worksheet there us no error (Maple 2017)

@Adam Ledger  

myproc:=proc() _passed end proc;

proc () args end proc


a, b, c



Download args.mw

@acer  @J F Ogilvie As you may know, the CODATA 2018 values relesed last year have many constants now exact (Planck's constant, Avogadro's constant, elementary charge, gas constant, Boltzmann's constant, speed of light (constant for a long time)), so the effort of an update now means very few changes will need to be made in the future.

@Carl Love i like that better, though the error message is still a bit obscure. Perhaps the type should be "listcontaining" rather than "speclist" ...

@Axel Vogt 



@tomleslie Thanks. I saw the code (only procedure definitions) but missed the system calls. Interestingly, the output of the procedure definition "monspt" in question shows it was using ListTools:Reverse by default.

@Lisa6 There is insufficient information.

@Lisa6 You must be running more code than you are showing. I can't run the code because I don't have a version with the convex package; you don't say which version of Maple you have.  @tomleslie and I agree that the message is very clear, so you will have to upload a worksheet that demonstrates the error.

@Preben Alsholm You're right. Actually now when I rerun the OPs worksheet (Maple 2017) I'm not getting any errors; it's just slow, Not sure why I thought that.

@Anthrazit  I hadn't thought of the case where the two units didn't have the same zero; that does seem to violate the ideas of quantity calculus. Actually, I am more worried about the case where you can convert 0 K to 0 kg. That's why I used the word "debatable"

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