I would think that
multinomial(1,prob,size=ntrials).sum(axis=0)
would be equivalent to
multinomial(ntrials,prob)
but the first gives a surprising result. (See below.)
Explanation?
Thank you,
Alan Isaac
>>> ntrials = 100000
>>> prob = N.arange(100,dtype=N.float32)/4950
>>> multinomial(1,prob,size=ntrials).sum(axis=0)
array([ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 990, 1058, 996,
1102, 1088, 1137, 1144, 1150, 1196, 1198, 1272, 1273, 1268, 1265,
1380, 1336, 1371, 1405, 1348, 1420, 1515, 1506, 1571, 1499, 1556,
1517, 1603, 1691, 1696, 1763, 1622, 1716, 1722, 1785, 1866, 1799,
1918, 1818, 1868, 1938, 2010, 1916, 1950, 1983, 2062, 2079, 2224,
2165, 2136, 2156, 2215, 2118, 2309, 2389, 2377, 2423, 2328, 2325,
2469])
>>> multinomial(ntrials,prob)
array([ 0, 27, 33, 55, 104, 104, 116, 153, 166, 181, 189,
199, 244, 262, 259, 303, 330, 343, 373, 360, 371, 437,
423, 470, 460, 550, 551, 497, 517, 593, 623, 623, 648,
660, 638, 718, 713, 754, 784, 831, 804, 868, 902, 851,
918, 932, 945, 972, 966, 1025, 1005, 1038, 1075, 1046, 1121,
1069, 1121, 1152, 1209, 1148, 1196, 1261, 1288, 1304, 1250, 1324,
1348, 1430, 1370, 1419, 1388, 1364, 1473, 1414, 1511, 1523, 1583,
1574, 1575, 1575, 1613, 1559, 1665, 1666, 1712, 1728, 1715, 1709,
1846, 1774, 1819, 1869, 1886, 1963, 1837, 1906, 1983, 1867, 1968,
1916])
>>>
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