I don’t understand the following is not typestable,

changing the `_p`

assignment to a `mapreduce`

call doesn’t help, subsetting `h`

or a `for`

loop helps:

```
function conf_int_sum{T}(p::T, h::Array{T}, eps::T)
b1 = zero(T)
b2 = one(T)
b = (b1 + b2) / 2
_p = sum(x -> (x >= b) ? x : zero(x), h)
while abs(_p - p) > eps
if _p > p
b1 = b
else
b2 = b
end
b = (b1 + b2) / 2
_p = sum(x -> (x >= b) ? x : zero(x), h)
end
return b
end
function conf_int_mapreduce{T}(p::T, h::Array{T}, eps::T)
b1 = zero(T)
b2 = one(T)
b = (b1 + b2) / 2
_p = mapreduce(x -> (x >= b) ? x : zero(x), +, h)
while abs(_p - p) > eps
if _p > p
b1 = b
else
b2 = b
end
b = (b1 + b2) / 2
_p = mapreduce(x -> (x >= b) ? x : zero(x), +, h)
end
return b
end
function conf_int_subset{T}(p::T, h::Array{T}, eps::T)
b1 = zero(T)
b2 = one(T)
b = (b1 + b2) / 2
_p = sum(h[h .>= b])
while abs(_p - p) > eps
if _p > p
b1 = b
else
b2 = b
end
b = (b1 + b2) / 2
_p = sum(h[h .>= b])
end
return b
end
function conf_int_for{T}(p::T, h::Array{T}, eps::T)
b1 = zero(T)
b2 = one(T)
b = (b1 + b2) / 2
_p = zero(T)
for i in h
if i >= b
_p += i
end
end
while abs(_p - p) > eps
if _p > p
b1 = b
else
b2 = b
end
b = (b1 + b2) / 2
_p = zero(T)
for i in h
if i >= b
_p += i
end
end
end
return b
end
# typestable:
@code_warntype conf_int_for(0.5f0, randn(Float32, 30, 30, 30), 1f-3)
@code_warntype conf_int_subset(0.5f0, randn(Float32, 30, 30, 30), 1f-3)
# not typestable:
@code_warntype conf_int_mapreduce(0.5f0, randn(Float32, 30, 30, 30), 1f-3)
@code_warntype conf_int_sum(0.5f0, randn(Float32, 30, 30, 30), 1f-3)
```