FP3.mw

Hi all,

I write this code with some matricial calculations.

There are two important parameters N and Digits (in red in the code).

For N=8, I can do the calculation with Digits=10. For N=10, to get the results (without overflow), I should give Digits=30.

I want to do the calculation for N=100 and higher.

I do not know how to do this. I have a PC with 4G of RAM.

Thank you

While I am working with a problem , suddenly the message 'Kernel connection lost' appeared. After that I restarted maple and then I opened my work sheet again , but I lost all my equations and data in the work sheet. I dont know why? All my work is total empty. 

How can I recover the work sheet data? Solutions are appreciated.

I have attached the lost work sheet for your reference. 

Thanking you.

Hello All,

I looked through the Maple help on PDE systems and pdsolve and the physics problems that appear there. THere are a number of single-PDE cases with initial / boundary conditions; but I couldn't find PDE systems with ics/bcs.

Would you have a (simple) example of a PDE system with its initial / boundary conditions? I am attempting to build understanding of the syntax and different options of "pdsolve". Examples seem to be a great way to learn how to solve PDE systems. One can then pdsolve the PDE system without ics; then add them, try different options etc.

Thank you!

Hello everybody.

In the attached file, you find 6 equations. All of these parameters are known except "pd" and "qd". How can I find these two unknowns from 6 equations??? It should be pointed out that, "pd" and "qd" must contain "ud", "vd","wd" and "rd".

Thanks in advance.

D.mw

I need a help about running the following codes..

restart:
d:=1:
s:=0.8:
c1:=sqrt((s)/Pi/r^3)/2 * (-sin(r*(u-1)^2/4/(s)+Pi/4)+sin(r*(u+1)^2/4/(s))/sqrt(2)):

c22:=-((u+1)/(4*Pi*r*sqrt(y-1)))*(exp(-r*y*(u+1)^2/(8*s)))*(sin(r*y*(u+1)^2/8/(s*(y-1))+Pi/4)/2+sin(r*y*(u-1)^2/8/(s*(y-1))+Pi/4)):
c2:=Int(c22, y= 1..100):

c33:=(sin(r*y*(u+1)^2/8/(s*(y-1))+Pi/4)+sin(r*y*(u-1)^2/8/(s*(y-1))+Pi/4))*(((d*s)/(Pi*(r^2)*y*sqrt(y-1))*exp(-r*y*(u+1)^2/8/s))-((d^2*sqrt((2*s^3)/(Pi*(y-1)*y^3*r^5)))*exp(d*(u+1)+(2*d^2*s)/(y*r))*erfc((r*y*(u+1)+4*d*s)/(2*sqrt(2*s*r*y))))):
c3:=Int(c33, y= 1..100):

g1:=c1+c2+c3:
g2:= unapply(Int(g1, r= 1..infinity, epsilon=1e-4,digits=7),u):
plot(g2, 0..10, numpoints=100);

Thank you!

VIM.3.mwHi,How do I make a graph and error table for exact and by using this method i.e VIM 

In the below file, I have tried to create tree using Graphtheory and export it to file. But exporting works only if I read the procedure twice and that too after running the procedure.

test.mw

testproc.txt

I was solving thos differential equiation using dsolve:

diff(P(t),t)=b*P(t)+m*t

dsolve({diff(P(t),t)=b*P(t)+m*t,P(t0)=P0});

where t0=2000 and P0=100 and m=9/50

Then, I found b setting at t=2001, P=2*P0=200, I applied fsolve to do this and the result was:

b=-1.5979...

To this point, Maple computes correctly. The problem starts when I tried to plot the result in a single 2D-graph (P vs t) using the computed value for b, the expression involved is:

P(t)=.1126460951*t-0.7049523744e-1-1.090463096*10^1390*exp(-1.597924898*t)

I wrote

plot( .1126460951*t-0.7049523744e-1-1.090463096*10^1390*exp(-1.597924898*t) , t=2000..2001);

The result was a blank plot, only the axes appeared even if I used the y=A..B option in the plot command. Is there a way to get the desired plot without having to evaluate the function at several points and then using this set of points to generate the plot: plot({[a,b],[c,d],[f,g]...})? (that worked, of course).

Thanks and regards.

P.S. I have used Maple for over 15 years now and I've plotted expressions even more complicated than this one, I found this very strange. I guess the 10^1390 has something to do this time, but I'm not sure...

I would like to import the code from Pg 90 on in the following document into Maple. Any suggestions for doing so with minimal editing required after pasting? http://mspace.lib.umanitoba.ca/xmlui/bitstream/handle/1993/14907/Huang_Liji.pdf?sequence=1&isAllowed=y

thanks,

I have an arrays of data. One for x values, and one for y values. How can I obtain a numerical integration of y for a range of x values?

I have tried defining a function of X using ArrayInterpolation(x,y,X) and then calling evalf(Int(f,xmin..xmax)) but that gives an error message. (I don't seem to be able to paste into this window) The error message says

"Error, invalid input: evalf expects its 2nd argument, n, to be of type posint, but received numeric."

I thought I was using a form of the equation right from the help system.

I also tried the 2D version of integration, but it returns the difference of my limits times my function name.

I aslo tried AdaptiveQuadrature, but I can't get that to work either.

-Mike McDermott

Newbie Maple user

by_parts.mwhi, plz someone tell me what I have to do for such type of error

i posted these ealier without any responds,pls i need some assistance my project supervisor has made it mandatory that i build a maple maplet of the bessel equation:

  i would have loved my maplet to have four knobs/sliders to vary the value of the parameters(T[g],T[0],k,p)  and also a play puase and stop bottons while texts boxes to type in the value of the unvaried parameters(gamma,G,alpha,delta,C[1],C[2]) and this maplet should show a 3d and 2d plot of the equation of which the various varying parameters can be varied to see effect on the plots.1.e 3d plots of (F against p and T[o]),(F against k and T[o]),(F against tortuosity and T[o]) which can be assigned to three different plot bottons but to be ploted on the same plotter and 2d plots of (F against p) and (F against k), (F against tortuosity) which can also be assigned to three different plot bottons but to be plotted on a second plotter aside that of the 3d plots.
i will really gratefull if anyone can help me out,thanks in advance<

Hi,
I'm new at maple and have a problem/question with the rkf45 numerical ODE Solver.

At first, my computer need a lot of time to calculate an analytic solution.
Therefor, I use the numerical way.

I have the following second order ODE:
ODE:=m*((D@@2)(x))(t)+d*(D(x))(t)+k*x(t) = d*(eval(diff(y(x), x), x = t))+k*y(t)
where y(t) is a realy big piecewise function, defined by me.

My initial conditions are:
x(0) = 0, (D(x))(0) = 0

With dsolve, I get the solution x(t) and the first derivative x'(t). I'm able to plot them with odeplot.

But...

Problem 1:
I need also the second derivative x''(t).
On this page: http://www.maplesoft.com/support/help/maple/view.aspx?path=dsolve%2Frkf45there is an example (eq 13 and 14) where the second derivative is useable, but this doesn't work with my differential equation.
I have add 
(D(D(x)))(0) = 0
to my initial conditions but then, I got the error that only 2 initial conditions are required.
What could I do, so that rkf45 returns also the second derivative?

Problem 2:
And in addition to this, I want to calculate with x(t), x'(t), x''(t) but I found no way to use them.
Only plots are possible.
If I reduce y(t) to a minimum, I can do everything with the analytic solution: plot, d/dt, d2/dt2, +, -, ...
I tried also to convert the procedure to a function but in this case, there is no way to derivate it.

Many thanks...