dharr

Dr. David Harrington

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17 years, 94 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

@nm I was not suggesting that the equivalent interface options would work - I tried that myself and found they did not. My point is that since these plot options appear under "interface" that they may be part of the "communication with the user interface" (see the interface help page), which is turned off when the worksheet is run "headless". From the RunWorksheet page: "The invoked worksheet runs "headless", meaning that it will not appear with a user interface." (my italics).

@FDS To convert Pa to mmHg use convert(27., 'units', 'Pa', 'mmHg'). You can just use x=0..Bloodpath as the odeplot range, with useunits=true.

To find the value at Bloodpath use sol(Bloodpath). I guess in this case you need to remove units.

Please upload your Maple worksheet using the green up-arrow option in Mapleprimes.

I don't know much about this, but in Maple 2015 FunctionAdvisor("branch_cuts",HeunC); returns "The location of the "branch cuts" for HeunC is unknown to the FunctionAdvisor"; compare FunctionAdvisor("branch_cuts",BesselJ); which returns "[BesselJ(a, z), And(a::(Not(integer)), z < 0)]". Likewise, MathematicalFunctions:-Get("branch_cuts",HeunC); returns empty. 

There is further information in other parts of the MathematicalFunctions package such as Evalf that may be useful.

@vicky2811 This is a general statement. Polynomials of degree greater than 5 do not have formulas for their roots (except in special cases). See e.g. https://en.wikipedia.org/wiki/Polynomial#Solving_equations

If you are interested in the infinite summation case (c=infinity) then it might be possible to find some formulas.

@mmead Glad you liked it. I modified it to also handle indexed variables, where the unit is the same for any index. See the edit in my original answer.

@tomleslie I should have noticed that! Vote up.

Please specify exactly what you want to do, and what the question is.

Please upload your worksheet using the green up-arrow (insert contents isn't working but insert link is).

Please upload the worksheet by using the green up-arrow, and let us know what the question is.

@jrive You used eval(subs(s = I*omega, xfer_in_s)). Simpler is to evaluate at s = I*omega: eval(xfer_in_s, s = I*omega). 
eval does automatic simplification where subs does not, and is usually what you want.

@tomleslie I just used that because the OP said "abs (x1(j)-x1(j-1)) < 10^-4 ". I also didn't understand the iteration requirement in relationship to the code given.

@awass Yes looks like you have to use the original PDE and work out the derivatives numerically from the function. See here for a post about that.

 

The error message is because you now have a system of two pdes, so need two initial conditions. Since u is your time variable, and your only initial condition is f(0,x)=g; you also need h(0,x)=something. The other conditions are boundary conditions. I don't use the numeric pde solver enough to know how to solve your problem.

@ I think the constant one is varepsilon, so not the same.

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