General schema of the method nsNMF approximates the original matrix as a product of two submatrices, W and H. Columns of W are basis experiments while rows of H constitute basis genes (columns of W and rows of H are separated for a better visibility). Coefficients in each pair of basis gene and experiment are used to sort conditions and genes in the original matrix. Conditions and genes with high values in the same basis gene and basis experiment are highly related in a sub-portion of the data and are co-clustered in the upper left corner of the sorted array.
Carmona-Saez et al. BMC Bioinformatics 2006 7:78 doi:10.1186/1471-2105-7-78