matmul(X;Y)

matmul(X;Y)

Example

Consider the following example:

<table cols="name, data_1, data_2, data_3, data_4" title="matmul example">
John,8,0,5,1;
John,2,0,1,1;
Mary,3,1,2,2;
Mary,4,1,2,2;
John,5,2,3,1;
John,6,2,3,1;
Mary,7,3,4,2;
Mary,1,3,0,2
</table>
<willbe name="matrix_0" value="g_matrix(name;;;data_1 data_2 data_3 data_4;0)"/>
<willbe name="matrix_0_inv" value="matinv(matrix_0)"/>
<willbe name="matrix_0_mul" value="matmul(matrix_0;matrix_0_inv)"/>

For every row, the matrix in matrix_0_mul will be the matrix multiplication of the matrices in matrix_0 and matrix_0_inv.

Since the matrices in matrix_0 and matrix_0_inv are the inverse of one another, the product of these matrices is the identity matrix.

For example, clicking on the > character in the first row of the matrix_0_mul column displays the result of the matrix multiplication of matrix_0 and matrix_0_inv for those rows where name is John.

You can see that the values along the diagonal are essentially 1 and that all the other values are essentially 0.