qr decomposition

Hi,

I was using matlab 7.4(R2007a)
Now I am using matlab7.11 (R2007b)
I compared the results of qr function
the input was
-0.002567107834001 0.000011594153560 -0.001071830879080
-0.000348397823395 0.002671433293894 0.000451336098179
-0.000000757384596 -0.000000006341647 0.000000956196323
I didn't got the same answer in the two version
the difference between the version is
Q1-Q

ans =

0 -0.2690 -0.0000
0 1.9818 -0.0000
0 -0.0001 0.0000

R1-R

ans =

0 0 0
0 0.0053 0.0012
0 0 0

if I dividing them I got
Q1./Q

ans =

1.0000 -1.0000 1.0000
1.0000 -1.0000 1.0000
1.0000 -1.0000 1.0000

R1./R

ans =

1.0000 1.0000 1.0000
NaN -1.0000 -1.0000
NaN NaN 1.0000

why is this differences?
Is this decomposition is not unique?
Is there is way to get from 7.11 the same results as 7.4?

Thanks,
Ditza

 

Hi,

You'd better try the comp.soft-sys.matlab forum
for your question.

Best wishes
Torsten.

 

oops!

I meant to post thier