>>> from variacions import var_prim

>>> r = var_prim([2.0, 2.03, 2.04], 0.04)
>>> r
-1
>>> r = var_prim([3.0, 3.01, 3.04, 3.05, 3.08, 3.1, 3.15], 0.04)
>>> r
5
>>> r = var_prim([4.01, 4.02, 4.03, 4.04, 4.08, 4.12], 0.04)
>>> r
3
>>> r = var_prim([1.96, 2.03, 2.04, 2.05, 2.06, 2.07, 2.08], 0.06)
>>> r
0
>>> r = var_prim([3.0, 3.01, 3.02, 3.09, 3.1, 3.2], 0.06)
>>> r
2
>>> r = var_prim([4.017, 4.02, 4.03, 4.04, 4.08, 4.12, 4.15], 0.005)
>>> r
1