Matrix diagonalis
Matrix diagonalis est matrix quadrata, cuius elementa omnia extra diagonalem principalem zeronis valorem habent. Saepe scribitur: D = d i a g ( d 1 , d 2 , … , d n ) = ( d 1 0 ⋯ 0 0 d 2 ⋱ ⋮ ⋮ ⋱ ⋱ 0 0 ⋯ 0 d n ) {\displaystyle D={\rm {diag}}(d_{1},d_{2},\dots ,d_{n})={\begin{pmatrix}d_{1}&0&\cdots &0\\0&d_{2}&\ddots &\vdots \\\vdots &\ddots &\ddots &0\\0&\cdots &0&d_{n}\end{pmatrix}}} . Matrix diagonalis, cui omnes numeri d 1 , d 2 , … d n {\displaystyle d_{1},d_{2},\ldots d_{n}} aequales sunt, matrix "scalaris" vocatur.