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Re: [Chimera-users] Sum of volume data values
by Thomas Goddard 13 Apr '06

13 Apr '06

Hi Eran, Ok, here is code to read an MRC file and print the sum of map values without using Chimera. You need Python, the Numeric Python module which handles multidimensional arrays and the VolumeData module from Chimera. Numeric is obtained from sourceforge: http://sourceforge.net/project/showfiles.php?group_id=1369&package_id=1351 The VolumeData module is in your Chimera distribution. chimera/share/VolumeData Here's an example running the script where I've set PYTHONPATH to have access to the VolumeData module: % env PYTHONPATH=/usr/local/chimera/share python2.4 volumesum2.py Sum of values of groel.mrc = 21720.8984375 Send future questions to chimera-users(a)cgl.ucsf.edu so others who have similar problems can benefit. I get that email just as fast. Tom ------- file volumesum2.py follows: # Script to print the sum of volume data values. # Does not need Chimera, just the VolumeData module and Numeric and Python. path = 'groel.mrc' # Read the MRC volume data and get the 3-D Numeric array. from VolumeData.mrc.mrc_format import MRC_Data data = MRC_Data(path) m = data.matrix() # Compute the sum of the elements of the volume matrix. import Numeric sum = Numeric.sum(m.flat) # Print the sum print 'Sum of values of', path, ' = ', sum ------- > Date: Wed, 12 Apr 2006 14:46:14 -0700 > From: Eran Shacham <eshacham(a)burnham.org> > To: Thomas Goddard <goddard(a)cgl.ucsf.edu> > Subject: Re: Sum of volume data values > > Hey Tom, > > Thanks for your reply. However, I would like to do that from within a > script I already wrote. i.e I would like to integrate a read_in method > for an MRC file, access it values and then calculate the sum. I would > like to avoid doing that by opening my file in Chimera at this stage of > the program. Can it be done by importing some of your code? > > Thanks, > Eran.

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Sum of volume data values
by Thomas Goddard 12 Apr '06

12 Apr '06

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(a)burnham.org> > To: Thomas Goddard <goddard(a)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

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Volume series tool
by Thomas Goddard 12 Apr '06

12 Apr '06

I wrote a Chimera tool to display sequences of volume data sets. They are displayed one at a time like a movie and a slider lets you choose any particular volume. It is intended for looking at 3-D optical microscopy time series, or a sequence of single particle density map reconstructions. Available on the Chimera experimental features web page: http://www.cgl.ucsf.edu/chimera/experimental/experimental.html Tom

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Rotation about an axis
by Jordan Benjamin 11 Apr '06

11 Apr '06

I'm trying to rotate a model about a specified axis and origin (preferably in global coordinates). I would like the rotation to be applied on top of whatever transformations have been applied already. I've looked at the documentation, including the programmer's FAQ and the source code for ConstrainedMove. I couldn't figure out how to do this, so I wrote the following function based on the ConstrainedMove code to do the rotation relative to another model: def rotate_around_model_axis(ref_model, model, origin, axis, angle_deg): mvo = apply(chimera.Vector, origin) vo = ref_model.openState.xform.apply(mvo) mva = apply(chimera.Vector, axis) va = ref_model.openState.xform.apply(mva) xf = chimera.Xform() xf.translate(vo) xf.rotate(va, angle_deg) xf.translate(-vo) model.openState.globalXform(xf) But, this doesn't seem to work as I'd intended. Is there a way to do this? Also, I'm a little confused about the coordinate system. It seems like the concept of a global coordinate system may not apply in Chimera the way I'm used to (like in Amira for example) since the camera is fixed. Is this true, or am I totally lost? Thanks in advance for any help you can provide. Jordan

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Newbie Questions
by Shafrir, Yinon (NIH/NCI) [F] 11 Apr '06

11 Apr '06

Hi there! I have two questions regarding using Chimera. How do you break a molecule to different models using the command line? I have a protein composed of 4 chains. It loads as one piece and designated model 0 I then select a single chain and I want to designate it as a new model. How do I do that using the command line (so I can write a script)? Also, when I select the chain and use the write command in this manner "write selected su1.pdb" the save dialog box pops up (even though I designated a filename) When I try "write selected 0 su1.pdb" nothing happens. My other question is: How can you force chimera to assign secondary type display to residues without editing the PDB file first? Say I want to show 30 residues that are not detected by ksdssp as beta sheets. Still, I want to represent them as beta sheets. Do I need to edit the pdb file? Best regards Yinon Shafrir

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Axis display
by Jordan Benjamin 10 Apr '06

10 Apr '06

Is there a convenient way to display the axes of the coordinate system (and preferably the origin)? Forgive me if this is addressed in the documentation, but I wasn't able to find it. Thanks, Jordan

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Collaboratory session
by Eduardo Sanz Garcia 10 Apr '06

10 Apr '06

I have been trying to set up a collaboratory session, but I could not see the model. I was able to chat and to see the pointer of the other person, anything else. Any idea? How can I know if it is a problem caused by the firewall?

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Move atoms with mouse
by Thomas Goddard 07 Apr '06

07 Apr '06

I put a tool on the Chimera experimental features web page that enhances the standard rotation and translation mouse modes (left and middle mouse buttons) to enable moving helices, strands, turns, PDB chains, any selected set of atoms, or multiscale model chains. http://www.cgl.ucsf.edu/chimera/experimental/experimental.html The molecular pieces are translated or rotated by dragging them with the mouse. It requires Chimera version 1.2206 or newer, and that is only available for Macintosh computers right now. Tom

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Newbie Questions
by Shafrir, Yinon (NIH/NCI) [F] 07 Apr '06

07 Apr '06

Hi there! I have two questions regarding using Chimera. How do you break a molecule to different models using the command line? I have a protein composed of 4 chains. It loads as one piece and designated model 0 I then select a single chain and I want to designate it as a new model. How do I do that using the command line (so I can write a script)? Also, when I select the chain and use the write command in this manner "write selected su1.pdb" the save dialog box pops up (even though I designated a filename) When I try "write selected 0 su1.pdb" nothing happens. My other question is: How can you force chimera to assign secondary type display to residues without editing the PDB file first? Say I want to show 30 residues that are not detected by ksdssp as beta sheets. Still, I want to represent them as beta sheets. Do I need to edit the pdb file? Best regards Yinon Shafrir

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Re: [Chimera-users] Read PDB file
by Elaine Meng 07 Apr '06

07 Apr '06

Hi Eduardo, Aha! You can see all the header information from the PDB file (the lines that come before the coordinates). How to do that: open the Model Panel (Favorites... Model Panel) and for the model you are interested in, click "attributes..." Click the "PDB Headers..." button at the bottom of the resulting attributes panel. Currently the header lines are shown in a different order than in the original PDB file (they are sorted alphabetically by type, but wthin each type such as REMARK the order is not changed), so you will have to scroll down to the SOURCE record to see the organism. Best, Elaine On Apr 7, 2006, at 11:29 AM, Eduardo Sanz Garcia wrote: > My real situation: > 1. I have File... Fletch by ID using 2ypi > 2. I didn't know what source organism they are using to get the > structure. > > Option a: go to www.pdb.org and obtain the information. > Option from chimera?: display the text file 2ypi.pdb to get the > necessary information? > > I was wondering if there is a command or function to display (the > text) of a PDB file. > ----- Elaine C. Meng, Ph.D. meng(a)cgl.ucsf.edu UCSF Computer Graphics Lab and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html

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