Using the C Math Library

Assigning to Multiple Elements 

Use a vector index to modify multiple elements in a matrix.

A colon index frequently appears in the subscript of the destination because it allows you to modify an entire row or column. For example, this code

mlfIndexAssign(&A, "(?,?)", mlfScalar(2), mlfCreateColonIndex(),
               mlfColon(mlfScalar(1),mlfScalar(3),NULL));

replaces the second row of an M-by-3 matrix with the vector 1 2 3. If we use the example matrix A,  A is modified to contain:

1 4 7
1 2 3
3 6 9

You can also use a logical index to select multiple elements. For example, the assignment statement

mlfIndexAssign(&A, "(?)", mlfGt(A,mlfScalar(5)),
               mlfHorzcat(mlfScalar(17), mlfScalar(17),
                          mlfScalar(17), mlfScalar(17),NULL));

changes all the elements in A that are greater than 5 to 17:

1     4    17
2     5    17
3    17    17

Assigning to a Single Element

Assigning to a Subarray