Matrix Norm

In mathematics, a matrix norm is a vector norm in a vector space whose elements (vectors) are matrices (of given dimensions).

Just like Vector Norm, matrix norm are used to measure the size of a matrix.

Frobenius Norm / Hibert-Schmidt Norm

The Frobenius Norm is given by $\Vert A{\Vert }_F=\sqrt{{\sum }_i^n{\sum }_j^n|a_{ij}{|}^2}$