The Student Room Group

Question about matrices (Gram Schmidt algorithm, QR factorization)

http://en.wikipedia.org/wiki/QR_decomposition#Example_3

We then rearrange the equations above so that the ai are on the left, using the fact that the ei are unit vectors:

How did they do this rearrangement?
Reply 1
They rearranged the equations to get, for example, from

u3=a3proje1a3proje2a3u_3 = a_3 - \text{proj}_{e_1} a_3 - \text{proj}_{e_2} a_3

to

a3=u3+proje1a3+proje2a3a_3 = u_3 + \text{proj}_{e_1} a_3 + \text{proj}_{e_2} a_3

and then used the definition of uiu_i and projea\text{proj}_e a in each case.

Quick Reply

Latest