## Data Dimensionality: Scalar, vector, matrix

- For many operations, it pays to think of a variable as being having
dimensions

Terms |
Dimensions |
Notation for an element |

Scalar |
0 |
x |

Vector |
1 |
y(i) |

Matrix |
2 |
z(i,j) |

- One of the largest causes of student error is mismatching dimensions
across an equals sign. If you have a vector on one side, you need a
vector on the other.
- Each element of a vector is a scalar
- In Matlab, you can see what each variable is from its display in the
workspace. Vectors are given as
(6051,1) or (1,6051) depending on whether they are column or row vectors,
which will probably not make much practical difference for us in this
course.

*last revision 1/11/2017*