Hi Eran, You can open your MRC file in Chimera, then open the following script "volumesum.py" which contains Python code to have the sum of all the volume values printed. Use menu entry File / Open to open both files. If you want to do this many times I can give you a modified version that creates a Chimera menu entry (under the Tools menu) that runs the script. Tom ------------ File volumesum.py follows: # Script to print the sum of volume data values. # Get the volume dialog object import VolumeViewer d = VolumeViewer.volume_dialog() # Get the volume data currently shown by the volume dialog dr = d.focus_region m = dr.full_matrix() # Compute the sum of the elements of the volume matrix. import Numeric sum = Numeric.sum(m.flat) # Print the sum to the reply log dialog. message = 'Sum of values of %s = %.6g' % (dr.full_name(), sum) print message # Display the reply log dialog. from chimera import dialogs dialogs.display('reply') -------------

Date: Wed, 12 Apr 2006 13:52:26 -0700 From: Eran Shacham <eshacham@burnham.org> To: Thomas Goddard <goddard@cgl.ucsf.edu> Subject: Reading mrc files

Hi Tom,

Can I use Chimera's code for reading in mrc files? Essentially, I would like to read in an mrc file and access its values. It is a mask file, and I simply need to add up it values. Any suggestions on how to do that easily with a Chimera module?

Cheers, Eran