Error in documentation about SAXIS

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Error in documentation about SAXIS

Postby qiaojunfeng » Fri Dec 16, 2016 5:38 am

Hello everyone, I'm currently involved in calculation of magnetic properties. When reading the documentation, I found VASP provide SAXIS-tag to control the magnetization direction, in documentation on page 124. However, after carefully inspection, I found there are some mistakes in the equations at the bottom of page 124.
For example, the definition of alpha should be the angle of the projection of (s_x, s_y, s_z) to Oxy plane and the cartesian vector x, beta should = atan(sqrt(s_x^2 + s_y^2)/s_z).
And actually, when I inverse the simultaneous equations between m_x, m_y, m_z and m_x^axis, m_y^axis, m_z^axis, I found the first equation on top of page 125 should be
m_x^axis = cos(beta)cos(alpha)m_x + cos(beta)sin(alpha)m_y - sin(beta)m_z, it should be minus sign before m_z.

So, could administrators correct mistakes in SAXIS tag and update the VASP manual?
In addition, does anyone has some materials about why the simultaneous equations between m_x, m_y, m_z and m_x^axis, m_y^axis, m_z^axis should look like these? Could someone provides me the mathematical derivation?

I appreciate all kinds of hints and materials, it will helps me a lot, Thank you!
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Re: Error in documentation about SAXIS

Postby admin » Fri Jan 13, 2017 2:50 pm

Thank you, the manual will be corrected.
The code itself is OK.
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