Once we have a sparse matrix, we can view it's sparsity structure with the command spy(A). An example with a randomly generated symmetric sparse matrix is given in Figure 5.3.

A sparse vector can be stored using a real array for the nonzero values together with an integer array containing the indices of these entries, as demonstrated by the following example.

Sparse matrices (vague definition): matrix with few non-zero entries. For practical purposes: an !×# matrix is sparse if it has $ min !, # non-zero entries. This means roughly a constant …

In the Compressed Row Storage (CRS) data structure, each matrix row i is stored as a compressed sparse vector consisting of pairs (j; aij) representing nonzeros.

In this book I introduce the topic of sparse and redundant representations, show the questions posed in this field, and the answers they get, present the flavor of the research in this arena, …

Where do we find sparsity in ML? Many real-world phenomena are sparse. Examples? Attack of the Clones! Should we store multiple copies of our sparse thing in different formats? What …

Sparse vs. Dense Matrices A sparse matrix is a matrix with enough zeros that it is worth taking advantage of them [Wilkinson]