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Symbolic Vector Manipulation Software?

  1. Mar 5, 2008 #1
    I would like to do something like a derivative with respect to a vector or really anything involving a vector (of known dimension, but unknown values) going in and a vector coming out:

    x= 4 by 1 vector
    A = 4 by 4 matrix
    diff( Transpose(x) * A * x, x)

    should return (1/2)*A*x

    Is there software that can do this? I am familiar with maple and matlab, but I don't think either of them can do this.

    Any suggestions?

    Thanks!

    David
     
  2. jcsd
  3. Mar 5, 2008 #2
    If A is symmetric it is [itex]2Ax[/itex], otherwise it is [itex](A+A^T)x[/itex] ! And I don't understand why you can not do with Maple or MATLAB. Do you mean handling vector calculus?
     
  4. Mar 5, 2008 #3
    ahh yea sorry 2Ax or (A+A^T)x is clearly correct.

    So that is would I would like to do, either with Maple or Matlab. Does anyone know how?
     
  5. Mar 5, 2008 #4
    Do what? The whole Maple is designed for this! Please, take the time for asking one exact question.
     
  6. Mar 5, 2008 #5
    Here is one exact question. I want to do this:

    with(LinearAlgebra);
    b:=Vector(x,3);
    B:=Matrix(A,3,3);
    f:=Transpose(b)*B*b;
    diff(f,b)

    but i get:
    Error, (in rtable/Product) invalid arguments
    when defining f

    am I going about this wrong?
     
  7. Mar 6, 2008 #6
    Now, I see your point but I can't give you the exact code because I don't have Maple on this computer. But I can tell you that it should be also related with ">>with(VectorCalculus);". Also, it would surprise me if it works without setting the dimension to, say, "m". Sorry for this sloppy answer but I have to access to Maple first to give a correct answer.
     
  8. Jun 21, 2008 #7
    trambolin, daviddoria, did you figure out the answer to this question? Thanks!
     
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