Day 5- Distance Matrix(Group J)

In mathematics,computer science and graph theory, a distance matrix is a matrix (two-dimensional array) containing the distances, taken pairwise, of a set of points. This matrix will have a size of N×N where N is the number of points, nodes or vertices (often in a graph).
For example, suppose these data are to be analyzed, where pixel eucledian distance is the distance matrix

Raw data

The distance matrix would be:

	a	b	c	d	e	f
a	0	184	222	177	216	231
b	184	0	45	123	128	200
c	222	45	0	129	121	203
d	177	123	129	0	46	83
e	216	128	121	46	0	83
f	231	200	203	83	83	0

These data can then be viewed in graphic form as a heat map. In this image, black denotes a distance of 0 and white is maximal distance.

I bioinformics, distance matrices are used to represent protein structures in a coordinate-independent manner, as well as the pairwise distances between two sequences in sequence space. They are used in structural and sequential alignment, and for the determination of protein structures from NMR orXRay Crystallography
Sometimes it is more convenient to express data as a similarity matrix