6 .Nd Visualize quivers with SDL
11 is a graphical program to interact with quivers. It is similar to
12 Keller's Java applet, which is published at
13 https://webusers.imj-prg.fr/~bernhard.keller/quivermutation/ , though
15 handles extensions such as half-weight edges and fat vertices.
17 starts, it shows a sample quiver, which does not have many interesting
18 properties. Hovering over a vertex or an edge will display relevant
19 information in the top right corner.
21 For convenience, edges are classified by color into three types, depending
22 on the specific edge weights they represent.
26 A black edge from vertex
31 .Dl ε_{ij} = ± d_{j} / GCD(d_{i}, d_{j})
32 .Dl ε_{ji} = ∓ d_{i} / GCD(d_{i}, d_{j})
33 where the signs are determined by the arrow's direction.
35 A gray edge has half the edge weights that it would have if it were black.
37 A red edge has any other weights. In general, red edges are rare during
44 The following controls are available. To cancel an action when input is
49 Clicking and dragging a vertex will reposition it onscreen. Clicking
50 and dragging empty space will reposition the entire quiver.
56 .Pc at a vertex, press
58 then click on the vertex.
60 To create a new vertex, press
62 then click where it should be placed. You will probably want to rename
66 To delete an edge or a vertex, press
68 then click the edge or vertex which should be deleted.
71 .Pq create a black edge if no edge is present, or add to an edge if one is present
72 between two vertices, press
74 then click the start and end vertices.
80 To increase the fatness of a vertex, press
82 then click the vertex. This may change how edges of that vertex are
83 calculated. The maximum fatness is system-dependent but
85 things tend to happen with low fatness.
89 but the vertex's fatness is decreased. The minimum fatness is 1.
91 To rename a vertex, press
93 then click the vertex to be renamed. The new name will be prompted
94 for. If the system has a unicode-compatible IME, entering unicode
95 characters should work without issue.
97 To save the current quiver, press
99 Depending on which packages are installed on the system, the filename
100 will be prompted for in one of a few ways. The following graphical file
101 choosers are known and probed for
115 If none is found, the filename will be prompted for onscreen. This prompt
116 is rather primitive, however.
119 .Pq and to discard the current quiver ,
122 A file will be prompted for in the same manner as the save dialog.
125 Example quivers may have been installed along with this program,
127 .Pa /usr/share/clav/ .
132 Edge weights are, for performance reasons
134 .Xr clav-mutation-find 1
135 .Pc , stored as fractions with
136 numerator and denominator in system-dependent ranges. While it probably
137 will not be an issue for
139 usage, causing edge weights to increase arbitrarily will eventually cause
141 to compute an unrepresentable edge weight. In this situation,
143 will terminate with a diagnostic message rather than display incorrect
146 .An S. Gilles Aq Mt sgilles@math.umd.edu