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Matrix Handling in Mathematica

  1. Jan 21, 2010 #1
    Hi,

    I ran this program:

    P = Table[Subscript[p, i, j], {i, 0, 3}, {j, 0, 2}]
    For[j = 0; i=0, j <= 2, j++, Subscript[p, i, j] = 2]
    MatrixForm[P]

    What is gives me is this:
    2 2 2
    p[1,0] p[1,1] p[1,2]
    p[2,0] p[2,1] p[2,2]
    p[3,0] p[3,1] p[3,2]


    If I change the program and rerun it:

    Clear[p]
    P = Table[Subscript[p, i, j], {i, 0, 3}, {j, 0, 2}]
    For[j = 0; i=1, j <= 2, j++, Subscript[p, i, j] = 2]
    MatrixForm[P]

    Now it gives me:

    2 2 2
    1 1 1
    p[2,0] p[2,1] p[2,2]
    p[3,0] p[3,1] p[3,2]


    I was expecting something like:
    p[0,0] p[0,1] p[0,2]
    1 1 1
    p[2,0] p[2,1] p[2,2]
    p[3,0] p[3,1] p[3,2]


    I want mathematica to erase its memory from the previous run, but nothing seems to work!


    Any suggestions?
     
  2. jcsd
  3. Jan 21, 2010 #2

    CompuChip

    User Avatar
    Science Advisor
    Homework Helper

    Did you try something like
    Clear[P]
    or
    For[every {i, j}, Subscript[p, i, j] = .;]
     
  4. Jan 21, 2010 #3

    Dale

    Staff: Mentor

    You might try ClearAll or Remove instead of Clear.
     
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