That’s how I think. But say if I+ is exactly same as I-, I use it twice. I got much lower R and Rfree, that means better fit. Isn’t good? And I’m also curious why.

Guangyu

From: Pavel Afonine <[email protected]>
Date: Friday, February 6, 2015 at 2:29 PM
To: Guangyu Zhu <[email protected]>, "[email protected]" <[email protected]>
Subject: Re: [phenixbb] refinement with anomalous data

If data set isn't anomalous then I don't see why you would want to refine against I+/I-.
Pavel

On 2/6/15 11:26 AM, Guangyu Zhu wrote:

What I meant is: I actually don’t have anomalous signal, so when I use I+/I-, kind of like I use Imean twice for each reflection. Can I do that?  My guess is that the resolution is low, so double reflection/parameter ratio really benefits the refinement, although overall the weight for x-ray term is not change, because rms bond and angle are similar.

Newer versions are better for my other refinement with higher resolution, but not this data set.

Guangyu

From: Pavel Afonine <[email protected]>
Date: Friday, February 6, 2015 at 2:12 PM
To: Guangyu Zhu <[email protected]>, "[email protected]" <[email protected]>
Subject: Re: [phenixbb] refinement with anomalous data

I use same data set for refinement, so Rfree is also marked for same reflection. The only difference is that I chose “Data labels” from Phenix IMEAN or I(+) I(-).

What I meant is that the IMEAN set is not the same as I(+),I(-) at least because the number of reflections in IMEAN is not the same as in I(+),I(-).

By the way, I use version 1.8.2 for refinement. Newer versions gives higher R/Rfree.

Should be the other way around...

Pavel