| Line 1: |
Line 1: |
| − | ''For the 1999 film, see [[The Matrix]].''
| + | Did you take the red pill or the blue pill? |
| − | | |
| − | A '''matrix''' (pl.: "matrices," [[Latin]] origin) is a complex ordering, in deliberate fashion, of [[numeral|numerals]]. In [[mathematics]], a "matrix" is a regular grid of numbers, which may be manipulated and solved through intermediate-level [[algebra]]. Matrix algebra is usually taught in [[sophomore]] [[high school]] level mathematics.
| |
| − | | |
| − | More formally, a matrix is an example of a rank-2 [[tensor]].
| |
| − | | |
| − | Alternately, a '''matrix''' may also be a complex ordering of a group of equivalent objects, especially where the order is imposed to gain incidental benefit from the [[synergy]] of the networked objects.
| |
| − | | |
| − | ==Mathematics==
| |
| − | In mathematics, matrices can be manipulated in a variety of ways, including [[addition]] and [[multiplication]].
| |
| − | | |
| − | ===Addition of matrices===
| |
| − | For example, to add two matrices, one would add their respective elements, thus:
| |
| − | | |
| − | <math>\begin{bmatrix}
| |
| − | x & y & z \\
| |
| − | 1 & 3 & 5 \\
| |
| − | 0 & 2 & 0
| |
| − | \end{bmatrix} + \begin{bmatrix}
| |
| − | 0 & 3 & 1 \\
| |
| − | 4 & 3 & {x+2} \\
| |
| − | 0 & 4 & v
| |
| − | \end{bmatrix} </math>
| |
| − | | |
| − | would equal
| |
| − | | |
| − | <math>\begin{bmatrix}
| |
| − | {x+0} & {y+3} & {z+1} \\
| |
| − | {1+4} & {3+3} & {5+(x+2)} \\
| |
| − | {0+0} & {2+4} & {0+v}
| |
| − | \end{bmatrix} = \begin{bmatrix}
| |
| − | x & {y+3} & {z+1} \\
| |
| − | 5 & 6 & {x+7} \\
| |
| − | 0 & 6 & v
| |
| − | \end{bmatrix} </math>
| |
| − | | |
| − | ===Multiplication of matrices===
| |
| − | To multiply two matrices, one uses the rule "go along the rows and down the columns". This is best illustrated by a specific example: a matrix times a vector:
| |
| − | | |
| − | <math>\begin{bmatrix}
| |
| − | a & b \\
| |
| − | c & d
| |
| − | \end{bmatrix} \begin{bmatrix}
| |
| − | e \\ f
| |
| − | \end{bmatrix}=\begin{bmatrix}
| |
| − | ae+bf \\
| |
| − | ce+df \end{bmatrix}
| |
| − | </math>
| |
| − | | |
| − | It is important to note that matrix multiplication is not commutative: in general, <math>AB \neq BA</math> for two matrices <math>A</math> and <math>B</math>. This has important consequences in [[quantum mechanics]].
| |
| − | | |
| − | To see why matrix multiplication works the way it does, we will use [[suffix notation]]. Consider first forming the product of two matrices, <math>AB</math>, which is itself a matrix. Then form the product <math>ABx</math>. Matrix multiplication is associative, so we can consider this as either <math>(AB)x</math> or <math>A(Bx)</math>. In suffix notation,
| |
| − | | |
| − | <math>
| |
| − | \sum_j(AB)_{ij}x_j = \sum_k A_{ik}(Bx)_k=\sum_{j,k}A_{ik}B_{kj}x_j
| |
| − | </math>
| |
| − | The vector <math>x</math> is arbitrary, so we can therefore deduce the rule for finding the product of two matrices:
| |
| − | | |
| − | <math>
| |
| − | (AB)_{ij}=\sum_k A_{ik}B_{kj}
| |
| − | </math>
| |
| − | | |
| − | ===Matrix concepts===
| |
| − | | |
| − | ====Basic concepts====
| |
| − | | |
| − | *[[Adjoint]]
| |
| − | *[[Determinant]]
| |
| − | *[[Diagonal matrix]]
| |
| − | *[[Identity matrix]]
| |
| − | *[[Inverse matrix]]
| |
| − | *[[Null, column and row space]]
| |
| − | *[[Scalar]]
| |
| − | *[[Trace]]
| |
| − | *[[Transpose matrix]]
| |
| − | *[[Vector]]
| |
| − | *[[Zero matrix]]
| |
| − | | |
| − | ====Advanced concepts====
| |
| − | | |
| − | *[[Basis]]
| |
| − | *[[Diagonalizeable]]
| |
| − | *[[Eigenspace]]
| |
| − | *[[Eigenvalue]]
| |
| − | *[[Eigenvector]]
| |
| − | *[[Gram-Schmidt process]]
| |
| − | *[[Hermitian matrix]]
| |
| − | *[[Jordan canonical form]]
| |
| − | *[[Laplacian]]
| |
| − | *[[Linear independence]]
| |
| − | *[[Matrix diagonalization]]
| |
| − | *[[Matrix reformation]]
| |
| − | *[[Matrix transformation]]
| |
| − | *[[Orthogonal matrix]]
| |
| − | *[[Orthonormal matrix]]
| |
| − | *[[Resultant]]
| |
| − | *[[Span]]
| |
| − | *[[Systems of linear equations]]
| |
| − | *[[Transcriptor]]
| |
| − | *[[Wronskian]]
| |
| − | | |
| − | [[Category:Linear algebra]]
| |
| − | [[Category:Computers]]
| |