U 9v f_ã@sTdZddlZddlmZddlmZddgZedƒd dd„ƒZed ƒd d d„ƒZ dS) zøFunctions for generating graphs based on the "duplication" method. These graph generators start with a small initial graph then duplicate nodes and (partially) duplicate their edges. These functions are generally inspired by biological networks. éN)Ú NetworkXError)Úpy_random_stateÚpartial_duplication_graphÚduplication_divergence_graphéc Csº|dks |dks |dks |dkr,d}t|ƒ‚||kr`. Notes ----- A graph of nodes is grown by creating a fully connected graph of size `n`. The following procedure is then repeated until a total of `N` nodes have been reached. 1. A random node, *u*, is picked and a new node, *v*, is created. 2. For each neighbor of *u* an edge from the neighbor to *v* is created with probability `p`. 3. An edge from *u* to *v* is created with probability `q`. This algorithm appears in [1]. This implementation allows the possibility of generating disconnected graphs. References ---------- .. [1] Knudsen Michael, and Carsten Wiuf. "A Markov chain approach to randomly grown graphs." Journal of Applied Mathematics 2008. réz3partial duplication graph must have 0 <= p, q <= 1.z+partial duplication graph must have n <= N.) rÚnxZcomplete_graphÚrangeÚrandintÚadd_nodeÚlistZ all_neighborsÚrandomÚadd_edge) ÚNÚnÚpÚqÚseedÚmsgÚGZnew_nodeZsrc_nodeZ neighbor_node©rúC/tmp/pip-unpacked-wheel-_lngutwb/networkx/generators/duplication.pyrs0     éc CsÂ|dks|dkr&d|›d}t |¡‚|dkr`. Returns ------- G : Graph Raises ------ NetworkXError If `p` is not a valid probability. If `n` is less than 2. Notes ----- This algorithm appears in [1]. This implementation disallows the possibility of generating disconnected graphs. References ---------- .. [1] I. Ispolatov, P. L. Krapivsky, A. Yuryev, "Duplication-divergence model of protein interaction network", Phys. Rev. E, 71, 061911, 2005. rrzNetworkXError p=z is not in [0,1].rz$n must be greater than or equal to 2FT) rrZGraphrÚchoicer r Z neighborsr Ú remove_node) rrrrrÚiZ random_nodeÚflagZnbrrrrrYs**         )N)N) Ú__doc__ZnetworkxrZnetworkx.exceptionrZnetworkx.utilsrÚ__all__rrrrrrÚs   I