RE: [ccp4bb]: I to F's

[Alexey Bochkarev <Alexey-Bochkarev@ouhsc.edu>]

***  For details on how to be removed from this list visit the  ***
***    CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html    ***

>   Using the quadratic relation obtained from 
> 
>  I + SIGI = (F+SIGF) (F+SIGF)
> 
>  2F SIGF + SIGF*SIGF = SIGI 
> 
>  So you can solve for SIGF.
>  When SIGF <<< F, SIGF ~~ SIGI/2F but this is not true for small F.
	[Alexei Botchkarev]  This is a particular case. One can modify the
general solution:
	by multiplying and dividing it on  sqrt(I + SigI) + sqrt(I)

	SigF = sqrt( I + SigI ) - sqrt ( I ) = SigI / [ sqrt(I + SigI) +
sqrt( I ) ]         [1]

	 When SigI << I, SigF ~~SigI/2 sqrt(I)
	When SigI >> I, SigF~~SigI/sqrt(SigI) = sqrt(SigI)

	When SigI ~~I, [1] provides a smooth connection of two extremes.

	Alexey
Alexey Bochkarev, Assistant Professor
Dept. of Biochemistry and Molecular Biology	
Univ. of Oklahoma Health Sciences Center, BRC-466	
P.O. Box 26901, Oklahoma City, Oklahoma  73190
Phone:	(405) 271-8346
FAX :	(405) 271-3910
mailto:Alexey-Bochkarev@ouhsc.edu
http://xtliris.ouhsc.edu/alexey.htm


>  
>