Thanks. I had mistakenly thought that linrange would retain the exact value of its end points, as does linspace.
My actual application is to reproduce the functionality of Matlab's optional histc output: [n,bin] = histc(x, edges) Here, (using Matlab notation), bin is an integer-valued vector of the same length as x such that bin(i) indicates which "bin" of edges is occupied by x(i). My Julian attempt at reproducing this function used a range named edges: edges = linrange(minimum(x), maximum(x), 20) bin = [find(edges[1:end-1] .<= t .<= edges[2:end])[1] for t in x] and it failed due to the issue demonstrated in my first post. I think that I could use linspace instead of linrange, but for other reasons a range is preferable in this application. Do we already have this binning functionality in some other built-in function? I checked Julia's hist(), but it provides only the first output of Matlab's bin. Thanks, --Peter On Tuesday, July 1, 2014 11:59:44 PM UTC-7, Ivar Nesje wrote: > > It is not a shocker to me. The problem is that Floating point numbers > represent binary fractions, and there is no way for linrange() to actually > get equidistant values you are looking for. It has to do approximations, > and thus it will sometimes miss closest possible value. That means equality > checks on floating point numbers should be used with extreme care. > > Our implementation reuses the old step size when indexing a FloatRange > with a range, but we could probably do better if we tried to keep the last > point equal. > > I reopened https://github.com/JuliaLang/julia/issues/7420 to keep track > of this issue. > > Ivar > > kl. 07:07:25 UTC+2 onsdag 2. juli 2014 skrev Peter Simon følgende: >> >> The final result below seems really strange to me. A bug? >> >> julia> x = linrange(1,10,20) >> 1.0:0.47368421052631576:10.0 >> >> >> julia> 10 .<= x # Gives expected result >> 20-element BitArray{1}: >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> true >> >> julia> 10 .<= x[end] # Gives expected result >> true >> >> julia> 10 .<= x[2:end] # The last entry in this result is a shocker to >> me! >> 19-element BitArray{1}: >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> false >> >> >> >> Here is the version info: >> >> >> julia> versioninfo() >> Julia Version 0.3.0-prerelease+3987 >> Commit 7dd97fa (2014-06-30 23:12 UTC) >> Platform Info: >> System: Windows (x86_64-w64-mingw32) >> CPU: Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz >> WORD_SIZE: 64 >> BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY) >> LAPACK: libopenblas >> LIBM: libopenlibm >> >>
