ranvar
ranvar, contextual keyword
The word ranvar
is a contextual keyword of the Envision language. It refers to the primitive data type ranvar
that represents a probability distribution over $\mathbb{Z}$.
r = poisson(2)
show table "" export: "/sample/oneranvar.ion" with r
followed by
read "/sample/oneranvar.ion" as T with
r : ranvar
show scalar "" a1b2 with same(T.r)
ranvar(T.a : number) 🡒 ranvar, aggregator
Returns the empiric ranvar from the given observations. Let’s $y_i$ be the $N$ observations, the empiric probability distribution is defined by:
$$P[X = x] = \frac{1}{N} | \{ y_i | y_i = x \} |$$
table T = with
[| as A, as B |]
[| 1, "a" |]
[| 2, "a" |]
[| 1, "b" |]
[| 2, "b" |]
[| 3, "c" |]
table G[gdim] = by T.B
where T.B != "c"
show table "" a1b4 with
gdim
ranvar(T.A)
group by gdim
Input numbers are rounded to the nearest integer.
The aggregator returns dirac(0)
on empty groups.
ranvar(T.a : number, T.w : number) 🡒 ranvar, aggregator
Returns the empiric ranvar from the given observations. Let’s $y_i$ be the $N$ observations of respective weights $w_i$, the empiric probability distribution is defined by:
$$P[X = x] = \frac{1}{\sum_{i=1}^N w_i} \sum_{ i | y_i = x} w_i$$
table T = with
[| as A, as B, as W |]
[| 1, "a", 1.0 |]
[| 2, "a", 1.0 |]
[| 1, "b", 0.5 |]
[| 2, "b", 2.5 |]
[| 3, "c", 1.0 |]
table G[gdim] = by T.B
where T.B != "c"
show table "" a1b4 with
gdim
ranvar(T.A, T.W)
group by gdim
The aggregator returns dirac(0)
on empty groups.