** Next:** CALCULUS AND LIMITS-RELATED KEYWORDS.
** Up:** REFLECTION SELECTION AND MODIFICATION.
** Previous:** LIMIt f
** Contents**

###

SCALe *f*

When this keyword is present, the data (amplitude and its standard deviation) will be
multiplied by the given constant *f*. The multiplication takes place after all
processing of the data is finished (ie, taking differences, squaring, etc). Downscaling
the data may be useful when the (extreme)
sharpness of the MaxEnt map suggests that the data
may be way off the absolute scale (on the high side, ie they must be downscaled).
I think that
rescaling the data at this stage is totaly unjustified. The only good excuse that
I can think of, is in the case of an isomorphous difference Patterson
function calculation : if the derivative
is non-isomorphous^{15}, then
there are good chances that with increasing resolution, the mean fractional isomorphous
difference will increase (instead of decreasing). This could fool maxent into believing
that there are good-strong data even at high resolution.
This, of course is correct, the only
problem being that
these ``strong'' high resolution data is noise from our point of view^{16}.

#### Footnotes

- ... non-isomorphous
^{15}
- Assuming that an isomorphous derivative ever existed ...
- ... view
^{16}
- These large
differences arise from the non-isomorphism and not from the heavy atom structure.

** Next:** CALCULUS AND LIMITS-RELATED KEYWORDS.
** Up:** REFLECTION SELECTION AND MODIFICATION.
** Previous:** LIMIt f
** Contents**
NMG, Nov 2002