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On Wed, 31 May 2006, Eleanor Dodson wrote:
> ...
>
> Kevin Cowtan wrote:
>
> ...
>
> > Qing Xie wrote:
> >
> >> Hi,
> >>
> >> Does anyone know the formula/or equation to calculate the
> >> Hendrickson-Lattman Coefficients from known Fmodel and phase?
> >> Once the formula is known, I can code it with fortran. Should I use
> >> degree or radian regarding phases?
> >>
> >> In addition, how to extract the A and B term (in complex A + iB) from
> >> the known Fmodel and phases as well?
> >>
> >> Thanks a lot!
> >>
> >> Qing
For the latter it's fairly easy:
A = |Fmodel| * cos(phase)
and
B = |Fmodel| * sin(phase)
Depending on your programming language, you will have to check how phases
have to be expressed (radians?) to get a sensible value for the
trigonometric functions sine and cosine. There may be sind and cosd
functions that take phase angles in degrees, this depends on the language
(Fortran from your post) and the compiler you're using. For Fortran, the
cos and sin functions have as arguments angles expressed in radians.
Fred.
--
s-mail: F.M.D. Vellieux (B.Sc., Ph.D.)
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