In computer graphics, square matrices are used for transformations and are very common. A column matrix consists of a single column. These notes, and most computer graphics texts, use column matrices to represent geometrical vectors. At left is a 4 x 1 column matrix. A row matrix consists of a single row.
Some books call a column matrix a column vector and call a row matrix a row vector .
This is OK, but can be ambiguous. In these notes, column matrices will be used to represent vectors and will also be used to represent geometric points.