dharr

Dr. David Harrington

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15 years, 224 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

@Carl Love This leaves "1" as nonlinear, which is not what the OP wanted.

@Carl Love OP's code looks at nops, so would have 3*x nonlinear. But perhaps the ground rule excluded that: "can be any combination of the given variables, that is, x, y, and z", which made me wonder if "y*y" would count.

@Stretto The rectangle and cursor mechanism in a code edit region works in the same way as for 1-D. I'm not aware of cases that don't work.

@Anthrazit Do(%MathContainer0 = evalf[3](a)); will give you 3 sig fig (not decimal digits, which is harder to arrange)

You can of course use a math container as a label by making it not editable.

@Christopher2222 Yes, the help says only grayscale tiff output is possible if it isn't coloured.

@Carl Love Thanks for catching that. I do know the rule, but was careless when I looked at the mass of Maple output - thinking I had a list of lists. I still find it confusing - when I look at the complicated mess that is evals before setting phi=Pi, which as you say is a Vector, it displays as a list of lists, with each of the entries having square brackets around it.

@Jjjones98 There is no two-sided (forward) laplace transform in inttrans. Not sure what the two-sided inverse laplace would be, since the contour already runs g-I*infinity to g+I*infinity.

If I change the last line to have i = 0 .. 200, 100 then I get a list of 3 numbers as expected (after about 45 seconds). I'm guessing it could be made more efficient by implementing the trapezoidal rule (or similar) for your integrals.

Of course I didn't guess. Nice implementation of a spigot algorithm.

@Jjjones98 invfourier(expr, w , t) doesn't make sense if expr contains t; you would be going from the time domain to the time domain.

@Jjjones98 So invfourier cannot evaluate it, without more information, perhaps specifying values of some constants. Working with any expression that has general roots of a quartic polynomial will be almost impossible. But something is very strange since you inverse laplaced into the time demain and then inverse Fourier from an expression with t in it, into another time domain. ??

@Jjjones98 This is the same file as the original.

@Jjjones98 yes, there is invfourier. See ?inttrans for help on the different forward and inverse transforms.

@NaeemQau I don't have Maple 2019, so can't reproduce the error. But with the second set of parameters you don't see the error, so why not work from there and provide an approximate solution.

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