Non-Negative Matrix Factorization: a Cone of Parts

Here are thirty columns of a non negative matrix, each a point with no negative coordinate, all in this corner of space.

Non negative matrix factorization writes A as W times H, with both factors non negative. The columns of W are parts, and every data column becomes a non negative mix of them: a point inside the cone the parts span.

The rest of the narration is in the book's Companion.