IMP logo
IMP Reference Guide  2.16.0
The Integrative Modeling Platform
resolution.md
1 Resolution in PMI {#pmi1_resolution}
2 =================
3 
4 Very generally, the _representation_ of a system is defined by all the
5 variables that need to be determined based on input information, including
6 the assignment of the system components to geometric objects (e.g. points,
7 spheres, ellipsoids, and 3D Gaussian density functions). It is common to use
8 a multiscale representation, where the system is represented using several
9 resolution scales simultaneously. The spatial restraints will be applied
10 to individual resolution scales as appropriate (for example, a cross link
11 may be applied at residue resolution, while an excluded volume restraint
12 may act on a more coarse representation of the system, such as a spherical
13 bead representing multiple residues).
14 
15 In PMI, the _resolution_ of a representation is simply the number of residues
16 per spherical bead. For example, resolution 10 represents the system using
17 a bead for every 10 residues, while resolution 1 uses a bead for each residue.
18 An all-atom representation is assigned a resolution of 0.
19 
20 Many PMI functions take a `resolution` parameter to specify which resolution
21 to act on. These functions use IMP::pmi::tools::HierarchyDatabase to get
22 the closest resolution if the exact resolution requested is not available.
23 
24 @note currently resolution is stored in the particle name. Ultimately it
25 is intended to use the IMP::atom::Representation decorator for this purpose
26 instead.
A decorator for a representation.