[Chimera-users] vop subtract map minRMS

[Roberto Marabini]

Hi,

  I  have two questions regarding the command "vop subtract" with the
option "minRMS".

1st question)

In the help page the option minRMS is defined as:

"the min RMS option can be used to scale othermap automatically to
minimize the root-mean-square sum of the resulting (subtracted) values
at grid points within the lowest contour of othermap."

Does this mean that the value that appears in the "Volume viewer"
window and labeled as "Level" is used to create a contour and all the
grid pints inside this counter are used to compute the scale factor?

2nd question)

If I understand the command, minRMS assume that the maps (let us
called them V1 and V2) are related by a multiplicative factor. That is

     V1 = V2 * f

where f is a scalar

In my case

   V1 = V2 * f1 + f2

that is, both maps are related by a multiplicative factor (f1) plus
and additive factor (f2). Is there any chimera command that compute
the average of a volume so I can force both volume to have the same
average?

   Thanks in advance.

  Roberto