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MaplePrimes Posts are for sharing your experiences, techniques and opinions about Maple, MapleSim and related products, as well as general interests in math and computing.

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    Testing objects for equivalence

    by: Karel Srot 216 Maple
    equivalence
    October 29 2006
    0  4

    UPDATE!!! I found that my blogpost appers in Maple reporter. You should know, that this blogpost was just a question about how to solve my problem better. Alec Mihailovs gave me and aswer and his solution of testing nested objects is much better. If you still want to use my piece of code, you should remove "set object" form "convertAMVStolist" procedure and replace all occurrences of "hastype" with "type" (as mentioned in comments below).


    This piece of code should be able to test two objects (not of every type) for equivalence (like testeq() does). The benefit is, that it should be able to test also nested objects. Is there any other and more simple way how to do that? How to test nested objects in sets?

    simultaneous sine functions

    by: sungyg 125
    October 29 2006
    0  5
    Hello! I try to solve the eq1, eq2, eq3, and eq4. I simplified the 4 equations to rs1 and rs2 to get the solution t3 and t5. Then, I check the solution by subsituting Eq(14) into Eq(10). The result is right. The rs1 equation was found by numerical tests. However, it is not correct for the eq1, eq2, eq3, or eq4. I do not understand why it is not correct. Please tell me the reason and how I can solve and obtain correct solution. The worksheet can be found in the File Manager Thank you for your time and help.

    Numerical Inverse Laplace Transform

    by: Alec Mihailovs 4495
    numeric inverse transform
    October 26 2006
    3  22
    Here is a simple procedure doing numerical inverse Laplace transform using Post's inversion formula, 
    ILT:=proc(f,s) local k,dig;
if nargs>2 and type(args[-1],'posint') then dig:=args[-1] 
else dig:=Digits fi;
proc(T) local t,d,a;
d:=dig;
a:=Limit();
t:=evalf(T,dig);
while op(0,a)='Limit' do
a:=evalf(Limit((-1)^k/k!*(k/t)^(k+1)*eval(diff(f,s$k),s=k/t),k=infinity),d); 
d:=2*d od;
evalf(a,dig) end end:

    Total Derivative

    by: brian bovril 914
    October 26 2006
    0  11
    Hi I wonder if anyone can assist with the Maple commmand to do total derivatives. For example, tan(theta)=1/x I want to know if there is a direct command to differentiate this equation w.r.t t (time). From memory, if I input D(tan(theta)=1/x), Maple outputs: tan(theta)D(theta)=-1/x^2 Dx the correct result should be: sec^2(theta)d(theta)/dt = -1/x^2 dx/dt thanks in advance Brian

    solve simultaneous sine functions

    by: sungyg 125
    October 26 2006
    0  1
    Dear Sir; restart; _EnvAllSolutions:=true; eqn1:=cos(omega[1]*t[1])+cos(omega[1]*t[2])=-1; eqn2:=cos(r*omega[1]*t[1])+cos(r*omega[1]*t[2])=-1; solve({eqn1,eqn2},[t[1],t[2]]); I try to get the solutions. It gives me very complicated answer. How do I interpret the results with assumed variables? Actually, I want to get the closed form solution. Could you help me about the problem? Thanks. Sung

    Numeric inverse laplace transform

    by: mbendame 34
    package
    October 25 2006
    1  8
    Maple has a package for computing analytic laplace and inverse laplace transforms, has anybody on this forum written a Maple code that computes the inverse laplace numerically?

    passing values with unit to a plot routine?

    by: Charles McCallum 12
    plot units plotting
    October 25 2006
    0  6
    Hi, I've been trying to teach my students how to use units in Maple calculations, and have figured out how to get around certain things like integration, etc. I don't think, however that you can pass say a vector that has units attached through a plotting routine in Maple. For example if an array M = [[1[[atm]], 4[[L]]], [0.1[[atm]], 0.35[[L]]]] is plotted with something like display([pointplot(M, color = red)]) Error, (in pointplot) incorrect first argument If I define the array w/o the units (using this method), there isn't an issue. There is more than one way to skin a cat in Maple, so maybe there is a way to do this that I don't know?

    File Manager Improved

    by: Will 1781
    convert format
    October 24 2006
    0  4
    A new version of the File Manager was just uploaded. This version now can convert more files to HTML in addition to Maple .mw worksheets. Now if you upload a .txt .mpl, .m, .html, .htm, .maplet, .mm, or .csv file the contents will automatically be converted to HTML. This allows you to view the file directly on MaplePrimes without having to download the file. You can copy the HTML code into your postings, allowing people to see your text files formatted correctly in your postings. When you upload an HTML file, the file's formatting is left intact. But the file's <head> section is removed so that when you paste the file in, it will not cause problems with the formatting of the site.

    Quick Entry tags Updated

    by: Will 1781
    October 24 2006
    0  0
    The links that appear at the top of entry forms have been updated, now when you click on "Upload/Use File or Worksheet", the following text is automatically inserted into your posting: Please replace this text with the link to your file. The link can be found in the File Manager This is to help remind you to copy and paste the link code from the File Manager back into your posting. If you have any comments on this feature, please comment on this post.

    a residue...

    by: edgar 669
    October 24 2006
    0  3
    the residue should be -1/Pi

    > residue(1/(1-exp(Pi)^s),s=2*I);

    > series(1/(1-exp(Pi)^s),s=2*I);

    >

    Import pictures

    by: Alec Mihailovs 4495
    format
    October 23 2006
    0  11
    It would be very helpful if Maple could not only export plots to gif and some other formats, but also import them by executing a command looking like PlotImport("something.gif");. In that case, for plots with huge outputs (like in Simulation of Brownian Motion), one could use plotsetup to export plot to gif, and then use PlotImport to display it in the worksheet (to avoid inserting picture manually). The worksheet size in that case would be considerably smaller (and, perha

    Help

    by: Mariner 667
    format
    October 23 2006
    0  0
    Many people seem to find difficulty in getting the information they need from Maple's help pages - witness the questions asked in MaplePrimes. Perhaps the moment has come to re-think the help search methods and rewrite many of the help pages.

    May I suggest that Maplesoft gives this priority in the coming months?

    J. Tarr

    1d phase portrait in Classic Maple

    by: Alec Mihailovs 4495
    phaseportrait plotting
    October 23 2006
    2  2
    I wrote a procedure for drawing a 1d phase portrait of an equation 
                            `x′`=f(x)
    in Classic Maple, 
    phase:=proc(f,r)
local a,b,bn,bs,U;
a:=op([1,1],plot(args));
bn:=-`-`(op([2,1..2],r));
bs:=[a[1,1],seq(`if`(
(a[i-1,2]-0.0001*bn*signum(a[i-1,2]))*(a[i,2]-0.0001*bn*signum(a[i,2]))<0,
`if`(a[i-1,2]*a[i,2]<0, (a[i-1,1]*a[i,2]-a[i-1,2]*a[i,1])/(a[i,2]-a[i-1,2]),
fsolve(f,subsop([2,1]=a[i,2]-0.02*bn,[2,2]=a[i,2]+0.02*bn,r))),NULL),
i=2..nops(a)),a[-1,1]];
b:=bs/bn;
U:=remove(x->abs(x[2,1])<0.04,
[seq([[b[i]+0.01,0],[b[i+1]-b[i]-0.02,0]],i=`if`(a[1,2]<0,2,1)..nops(b)-1,2),
seq([[b[i+1]-0.01,0],[b[i]-b[i+1]+0.02,0]],i=`if`(a[1,2]<0,1,2)..nops(b)-1,2)]);
plots[display](plots[arrow](
U,width=0.02,head_length=0.04,view=[b[1]..b[-1],-1..1],color=blue),
plots[pointplot](map(x->[x,0],b[2..-2]),symbol=circle,symbolsize=19),
plots[textplot](map(x->[x/bn,-0.07,sprintf("%.2f",x)],bs[2..-2])),
axes=none)
end:
    It works as in the following example for f(x)=sin(x), 
    phase(sin(x),x=-8..8);

    Simulation of Brownian Motion

    by: Alec Mihailovs 4495
    October 22 2006
    5  8
    One-dimensional Brownian motion can be simulated using the following (modified from the version posted here originally) procedure,

    bookmarks for help

    by: roman_pearce 1703
    October 20 2006
    0  0
    I find that when I'm working on something new I consistently end up reading the same set of help pages over and over. The "History" option in the help system has been very useful to me, but I would like to see a "Bookmarks" option added to Maple's help system as well.
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