This is an old version, view current version.

5.7 Broadcast functions

The following broadcast functions allow vectors, row vectors and matrices to be created by copying a single element into all of their cells. Matrices may also be created by stacking copies of row vectors vertically or stacking copies of column vectors horizontally.

vector rep_vector(real x, int m)
Return the size m (column) vector consisting of copies of x.

row_vector rep_row_vector(real x, int n)
Return the size n row vector consisting of copies of x.

matrix rep_matrix(real x, int m, int n)
Return the m by n matrix consisting of copies of x.

matrix rep_matrix(vector v, int n)
Return the m by n matrix consisting of n copies of the (column) vector v of size m.

matrix rep_matrix(row_vector rv, int m)
Return the m by n matrix consisting of m copies of the row vector rv of size n.

Unlike the situation with array broadcasting (see section array broadcasting), where there is a distinction between integer and real arguments, the following two statements produce the same result for vector broadcasting; row vector and matrix broadcasting behave similarly.

 vector[3] x;
 x = rep_vector(1, 3);
 x = rep_vector(1.0, 3);

There are no integer vector or matrix types, so integer values are automatically promoted.

5.7.1 Symmetrization

matrix symmetrize_from_lower_tri(matrix A)

Construct a symmetric matrix from the lower triangle of A.