Macro matrix_expr 

macro_rules! matrix_expr {
    () => { ... };
    (;$domain:expr) => { ... };
    ($x:expr) => { ... };
    ($x:expr;$domain:expr) => { ... };
    ($($x:expr),+) => { ... };
    ($($x:expr),+;$domain:expr) => { ... };
    ($($x:expr,)+) => { ... };
    ($($x:expr,)+;$domain:expr) => { ... };
}

Creates a new matrix as an Expression, optionally with some index domain.

For usage details, see matrix!.

To create a matrix expression from a Vec, use [into_matrix_expr!].