[julia-users] linspace question; bug?

[Páll Haraldsson]

I mistook third param for step, and got confusing error:


julia> linspace(1, 2, 1)
ERROR: linspace(1.0, 2.0, 1.0): endpoints differ
 in linspace(::Float64, ::Float64, ::Float64) at ./range.jl:212
 in linspace(::Float64, ::Float64, ::Int64) at ./range.jl:251
 in linspace(::Int64, ::Int64, ::Int64) at ./range.jl:253

julia> linspace(1.0, 2.0, 1)
ERROR: linspace(1.0, 2.0, 1.0): endpoints differ
 in linspace(::Float64, ::Float64, ::Float64) at ./range.jl:212
 in linspace(::Float64, ::Float64, ::Int64) at ./range.jl:251


It may not matter too much to get this to work (or give helpful error); I 
went to debug and found (should num/len be Integer? see inline comments):


immutable LinSpace{T<:AbstractFloat} <: Range{T}
    start::T
    stop::T
    len::T # len::Integer, only countable..
    divisor::T
end

function linspace{T<:AbstractFloat}(start::T, stop::T, len::T)

#long function omitted

function linspace{T<:AbstractFloat}(start::T, stop::T, len::Real) # change 
to len::Integer, is this for type stability reasons, or to handle Rationals 
somehow?
    T_len = convert(T, len)
    T_len == len || throw(InexactError())
    linspace(start, stop, T_len)
end
linspace(start::Real, stop::Real, len::Real=50) =  # change to 
len::Integer=50
    linspace(promote(AbstractFloat(start), AbstractFloat(stop))..., len)