Re: diffusion tensor related -- January 09, 2007 - 01:42

On 1/3/07, Chris MacRaild <c.a.macraild@xxxxxxxxxxx> wrote:
> On Fri, 2006-12-29 at 12:12 +0800, Hongyan Li wrote:
> > Dear relax users,
> > I am trying to run relax using spheroid model. I am a bit confused how to 
> set
> > diffusion tensor. I tried r2r1_diffusion to get Diso and Dper and Dpar, 
> Theta
> > and Phi, then input these values into the script 
> (sample_script/model-free.py)
> > and in this script "diffusion_tensor.init(name, (2e-8, 1.3, 60, 290),
> > param_types=0, spheroid_type='prolate', fixed=1)" I guess the values should 
> be
> > tm and Da, theta and Phi (is the second value 1.3 Da? seems not right cause 
> I
> > got 5e7 for this)
>
> It looks to me like this line in model-free.py was not properly updated
> when the diffusion_tensor.init() function was changed in relax a few
> versions back. The line should read:
>
> diffusion_tensor.init(name, (2e-8, 1.3, 60, 290), param_types=2,
> spheroid_type='prolate', fixed=1)
>
> ie. the value 1.3 is actually Dr (= Dpar/Dper), not Da

Just a small point, I think you meant to say Dratio rather than the
asymmetric or rhombic parameter Dr.  The relax user manual explains
all the possible parameter combinations and how they relate to the
'param_types' argument.

Edward