math - How to : Generate bimodal distribuctions -

im working on problem need work bimodal histograms.like on example below.

but im getting hard times looking them. im working histograms vector, in exemplo below. there way generate random bimodal histograms programming language? (since can save histograms txt file)

histogram 1 

8029, 41, 82, 177, 135, 255, 315, 591, 949, 456, 499, 688, 446, 733, 712, 1595, 2633, 3945, 6134, 9755, 9236, 11911, 11888, 9450, 13119, 8819, 5991, 4399, 6745, 2017, 3747, 1777, 2946, 1623, 2151, 454, 3015, 3176, 2211, 1080, 391, 580, 750,

histogram 2

8082, 4857, 1494, 2530, 1604, 1636, 1651, 1681, 1630, 1667, 1636, 1649, 1934, 1775, 1701, 1691, 1478, 1649, 1449, 1449, 1503, 1475, 1497, 1398, 1509, 1747

histogram 3

50, 226, 857, 2018, 1810, 1795, 1840, 1929, 1942, 1693, 1699, 1547, 1564, 1556, 1451, 1439, 1448, 1357, 1428, 1419, 1383, 1705, 1670, 1777, 1826, 1865, 1897 .

you parameterize unimodal distributions peaks want them, , choose among them desired relative proportions.

for instance, 100k observations following generating formula:

produced histogram:

where 40% of time generate exponential mean of 3, 20% of time n(3, 0.5), , remainder of time n(7,1).

adjust distributions, means, standard deviations, , proportions suit.