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Mathematical notation to multiply matrix elements

  1. Apr 18, 2010 #1
    Hi all,

    I need to figure out the mathematical notation to multiply matricies A and B = C so that...

    If matrix A is...
    a1
    a2
    a3
    a4
    a5

    and matrix B is...
    b1
    b2
    b3
    b4
    b5

    so that matric C is...
    a1*b1
    a2*b2
    a3*b3
    a4*b4
    a5*b5

    Would this involve using a the transverse of a matrix?

    Thanks.
     
  2. jcsd
  3. Apr 18, 2010 #2

    CRGreathouse

    User Avatar
    Science Advisor
    Homework Helper

    Looks like the componentwise multiplication of vectors to me.
     
  4. Apr 18, 2010 #3

    Mark44

    Staff: Mentor

    That is, the dot product of two vectors.
     
  5. Apr 18, 2010 #4
    When I calculate the doct product of those two matricies, won't I get a single scalar value?
     
  6. Apr 18, 2010 #5
    Okay, I found what I was looking for. It's called a Hadamard product. The Hadamard product A and B produces matrix C so that C_i,j = A_i,j * B_i,j.

    Is there any way to compute this using common mathematical operators (such as inverse, transpose, dot product, cross product)?

    The reason I ask is because I'm doing a homework assignment in Mathcad calculating power requirements of a car at certain speeds. I'm just assigning the speeds to a single-column matrix and the resistant forces to a single-column matrix. I want to output a power matrix.

    If I can't figure it out, I'll just have to manually assign a force and velocity variable to each speed, but there must be a way to do this more easily.
     
  7. Apr 19, 2010 #6

    Fredrik

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I don't know what Mathcad is, but in Matlab you would write this sort of multiplication as .* instead of just *. (That last period just ends the sentence of course).
     
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