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#### 23.1.2 Matrices

Matrices are handled with speed and memory-efficiency in mind. This means that assigning a matrix to a variable will create a reference to, not a copy of the matrix. If the matrix is modified all references to the matrix point to the modified object (See `copymatrix` for a way of avoiding this):

    (%i1) M1: matrix([0,0],[0,0]);
                                [ 0  0 ]
    (%o1)                       [      ]
                                [ 0  0 ]

    (%i2) M2: M1;
                                [ 0  0 ]
    (%o2)                       [      ]
                                [ 0  0 ]

    (%i3) M1[1][1]: 2;
    (%o3)                           2

    (%i4) M2;
                                [ 2  0 ]
    (%o4)                       [      ]
                                [ 0  0 ]

Converting a matrix to nested lists and vice versa works the following way:

    (%i1) l: [[1,2],[3,4]];
    (%o1)                   [[1, 2], [3, 4]]

    (%i2) M1: apply('matrix,l);
                                [ 1  2 ]
    (%o2)                       [      ]
                                [ 3  4 ]

    (%i3) M2: transpose(M1);
                                [ 1  3 ]
    (%o3)                       [      ]
                                [ 2  4 ]

    (%i4) args(M2);
    (%o4)                   [[1, 3], [2, 4]]

Next: Vectors, Previous: Dot, Up: Introduction to Matrices and Linear Algebra [Contents][Index]