Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.
  1. What do Q and R stand for?

  2. Why must the diagonal entries of R be positive instead of just nonzero?

share|improve this question
    
$A=QR$, $Q$ is an orthogonal matrix and $R$ is an upper triangular matrix. –  Mhenni Benghorbal Nov 28 '12 at 6:48
    
Thanks. I know that. I mean what names do Q and R stand for? Queer Rainbow? Quixotic Renegade? –  gondonla Nov 28 '12 at 7:02
    
See here under "computing the $QR$ decomposition" and you will find the answer for part $(2)$ of your question. –  Mhenni Benghorbal Nov 28 '12 at 7:50
    
+1 for "what do Q and R stand for". My guess was that ORthogonal starts with O and tRiangulaR ends with R, but OR is a logical operator so they call it QR. Alternatively QR are two subsequent letters and M (matrix), n (count) and P (often used in definitions here) are used. In that case you would start namefinding from LU. –  naxa Jan 30 '13 at 14:28
add comment

Know someone who can answer? Share a link to this question via email, Google+, Twitter, or Facebook.

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.