Re: [ccp4bb] Obtaining relationships between two cross rotation solutions?

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

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Subject: Re: Obtaining relationships between two cross rotation solutions?
From: Doug Ohlendorf ohlen {- at -} UMN {- dot -} EDU
Date: 2009-02-03

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From: Dirk Kostrewa kostrewa {- at -} LMB {- dot -} UNI-MUENCHEN {- dot -} DE
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Subject: Re: Obtaining relationships between two cross rotation solutions?
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2009-02-04

I presume theta1 theta2theta3 are eulerian angles?

When theta2 ~ 0, you can onlyy define theta1+theta2 so solution 1 is
effectively the identity;

theta1+theta3 = 360 (ie 0) theta2~0. theta3 not defined - that
generates the identity matrix.

When theta2 ~ 180, you can onlyy define theta1-theta2 so solution 2 is _
0 180 undefined - a matrix defining a 180 degree rotation about the
theta2 axis. (probably crystallographic..)

And almost certainly 7 and 8 are symmetry equivalents. theta1 theta2
theta3 and 180+theta1 180 -theta2 -theta3

But to be sure you have to know the angle convention used for defining
the Eulerian system.

The old fashioned programs listed all equivalents, abd there is rotation
checking programs. ROTMAT is one..
Eleanor

Francis E Reyes wrote:
> I have trouble with visualizing things in three dimensions so I'm
> trying to figure out the relationship between two cross rotation
> functions (given as theta1, theta2, theta3).
>
>
> Is there a program or webapp that'll tell me whether two rotation
> solutions are related by a 180/90/60/whathaveyou axis?
>
> e.g.
>
> The space group is P4(1)
> The top few cross rotation solutions are:
> ! index, theta1, theta2, theta3, RF-function (EPSIlon= 0.25)
> 1 173.333 2.630 186.481 0.0907
> 3 353.426 180.000 353.426 0.0879
> 7 98.807 147.925 67.347 0.0608
> 8 279.440 30.322 292.587 0.0602
> 10 292.696 168.784 294.156 0.0562
> 12 233.216 30.322 246.364 0.0511
>
>
> Is index 1,3 related how about 7,8?? What is the relationship between
> the pair 1,3 and 7,8 ?
>
> Thanks
>
> FR
>
> ---------------------------------------------
> Francis Reyes M.Sc.
> 215 UCB
> University of Colorado at Boulder
>
> gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D
>
> 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D
>
>

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Obtaining relationships between two cross rotation solutions?
From: Doug Ohlendorf ohlen {- at -} UMN {- dot -} EDU
Date: 2009-02-03

Next message:
Subject: Re: X-ray photon correlation length
From: Dirk Kostrewa kostrewa {- at -} LMB {- dot -} UNI-MUENCHEN {- dot -} DE
Date: 2009-02-04