Maple Questions and Posts

These are Posts and Questions associated with the product, Maple
I have searched and googled all over places, just couldn't figure out how to save all the variables in the current workspace. save all, "myfilename.m" doesn't work at all. There is no such usage in the documentation. When you have many variables, how do you save them all? ----------------- Two quick side questions(without opening a new thread): Q1: If you have two statements joined together, how to separate them? I am using GUI in Maple 11: Example: statement_x; statement_y; how to break them into: statement_x; statement_y; Every time I hit "Enter" after statement_x, both got executed. After long waiting(they happened to be both huge and messy), messy results were printed out, I have to scroll many pages, but these two statements were still together. Annoying!
Codegen: floating point constants vs. symbolic constants Let's say in a complex-valued function, constants such as 1/2, 1/4, etc. are involved. I found, upon some experts' advice, the symbolic computations are different. If one expression is too hard to evaluate or simplify, changing the constants back and forth between floating point constants 0.5, 0.25, etc. and symbolic constants 1/2, 1/4 or one way or the other will often help. However, our end goal is code generation and translation into C or Fortran. Will the efficiency and accuracy be different in the translated end results for the floating point constants and symbolic constants cases? I roughly found no difference.
Gradient: thought comparison of the codegen version and the symbolic version. This is something I don't understand. There are two ways of obtaining the gradient of a function: (1) codegen uses auto-differentiation; (2) derive the partial derivative symbolically. Both can be translated into C or Fortran code, since my end goal is the C or Fortran code. The documentation claims the auto-differentiation is more efficient. I don't understand. Any more complete views about this matter? Does auto-differentiation win both in accuracy and efficiency? Or perhaps there is a trade-off between efficiency and accuracy? I just wanted to hear more opinions from your experience. Thanks a lot!
I recently switched from XP to an Intel Mac (OS X 10.4.9); I am using Maple 9.5 on the Mac. In contrast to Win XP the backspace key does'nt work as expected (delete the previous character). Is there any other key or combination of keys for deleting characters? Regards Wilhelm
In MAPLE one has the next command. > for n from 1 to 3 do n=2 then next; end if; print(n); end do; I was wondering how you could have more than one next. So instead, skip over two numbers, or three.. etc?
Hi all, If I have an expression and it involves computations with extremely large numbers. Double precision is bound to fail in my case. And when I used Matlab 2007a's symbolic toolbox, which I believe uses Maple 10 or Maple 9's engine, it supposedly should always return correct value, because its symbolic, with infinite precision. But it still fails for some parameters which makes the numbers too large. Now if I compute the same expression in Maple 11, it is even worse. The calculation fails for a lot more parameters. The failing parameter set for previous Maple version is now a subset of the failing parameter set for the Maple 11. The difference is huge -- Maple 11 gives wrong values almost all the time, even for very friendly parameters.
Hi all, Did you discover the same mysterious thing about the command execution time in Maple? Here is my observation: If I have been using this session for a long time and then if I issue a long-processing command, such as simplification of a very complicated expression, etc. After a while, Maple will get into "steady state": it keeps running and running, without consuming more memory and showing more activity, the time even counts towards 10000 second, etc. If based on this, I think the expression is really too complicated for it to simplify, then I am wrong. After rebooting the PC, and relaunch Maple, and start the same command to simplify the same expression, it generated a result within 15 minutes, successfully...
How can I make maple read data from file.dat and fit it in a nonlinearfit.thanks.R
A little under two years ago, I started working on a little project we have here at NCSU. I should perhaps devote another blog entry to discussing that lovely little project... Anyway, there's a lot of Maple code in this project (as it is based in Maple), and I've had to untangle and understand what multiple programmers have done over the years. Last year, I came across one piece of code that I thought was exploiting a bug in Maple: We would take a long string of commands and parse the entire string with a single parse() command. I could never get a Maple worksheet to reproduce those results obtained from piping the command into Maple from the command line. Weird, no?
For each of the definitions

p := proc( x :: float ) :: float; x^(2/3) end proc:
p := proc( x :: float ) :: float; x^evalf((2/3)) end proc:

i get an error by calling Compiler:-Compile( p ):

"Error, (in printtab[CodeGeneration:-Names:-Rational])
rational numbers and arithmetic are not yet supported"

Any suggestions what to do (except manually converting
all exponents to floats)?

Edited to add: for example the following does not work:

c := proc (S::float,...
What's wrong with my "asympt"? Hi all, I want to find out the order of growth/decay of expression CCP1(attached below). CCP1 is a sub-expression of my huge expression(which Maple couldn't handle). The goal is to find the functional form for my expression as "v" and "t" approaches +infinity, so that I can bound the error after truncating it, because I am using this as an integrand. The original huge expression is known to be fast decay in "v" -- I suspect the asympotic order is of exp(-a*v)/(v+b)^n. But this sub-expression might be decay, it may grow at +infinity. The goal is to find out the asymptotic order of growth/decay so that when I combine with the results from other expressions I can get the overall decay order.
I have been trying to solve the following differential equation with 2 starting conditions. (It's the equation of a mechanical vibration). >diff(x(t), t, t)+4*Pi^2*x(t) = 200*sin(hoekvers*t) beginvw:=x(0)=5,D(x)(0)=0; The result: >Opl:=dsolve({DV,beginvw},x(t)); >Opl:=x(t) = -100*sin(2*Pi*t)*hoekvers/(Pi*(4*Pi^2-hoekvers^2))+5*cos(2*Pi*t)+200*sin(hoekvers*t)/(4*Pi^2-hoekvers^2) Now I want to plot the graphic of this vibration when hoekvers=2*Pi. (In that case there is resonance) I get the error dived by zero. As you see the numer is zero when I fill in 2*Pi. For 2*Pi+0.000000000001 I get no error and a good graphic but this is not a good and exact method according to me.
Is there any way that I can get MAPLE to check through an ordered set and return the first integer value? So if the set were; {2,x,h} it would return 2 {r,h,x} it would return () {3,4,5} it would return 3
Waterloo Region, where our head office is located, has been called "The Quilt Capital of Canada". So a couple of years ago, I'd created a worksheet to generate a traditional "Log Cabin" quilt. I've made some minor updates to the example and added a "Trip Around the World Quilt". Having made a few quilts by hand myself, I can definitely say that it's easier to create a Maple one!
Is there a way to save results to file instead of the console/display? My expressions got too long and they occupy huge space on screen and scrolling is horrible now. Of course I can hide the content of the display by using ":". However, I do need to use(copy & paste to other applications) the very last output of results(it is very long). Is there a way to specify or redirect the output to file so after a while I just need to open the output file to use that long expression? Thanks a lot!
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