I think I found a replacement for eye in julia 7.0 julia> c=rand(Int8,4,4) 4×4 Array{Int8,2}: 44 -79 36 116 -14 -64 -49 -52 77 -110 -20 118 -119 -57 -78 90 julia> @btime Matrix{eltype($c)}(I,size($c)) 47.614 ns (1 allocation: 112 bytes) 4×4 Array{Int8,2}: 1 0 0 0 0…

You can just use one(A) or oneunit(A) (depending on how you want to handle the dimensionful case) for the equivalent of eye(A) for square matrices. (eye also worked for non-square matrices, but I don’t know of a non-verbose equivalent on 0.7.)

Should not the deprecation help the programmer as much as possible? Here the most common subcase has a nicer/shorter deprecation, so should not this be mentioned in the deprecation message?

[image] Jean_Michel: Should not the deprecation help the programmer as much as possible? Here the most common subcase has a nicer/shorter deprecation, so should not this be mentioned in the deprecation message? Auto-deprecations are done in Julia with @deprecate oldfunc(args...) newfunc(newar…

In my case: to construct the generators of a Coxeter group from the Cartan matrix, you get the i-th one by subtracting the ith line of the Cartan matrix from the corresponding line of the identity matrix.

[image] Jean_Michel: In my case: to construct the generators of a Coxeter group from the Cartan matrix, you get the i-th one by subtracting the ith line of the Cartan matrix from the corresponding line of the identity matrix. If you have a Cartan matrix C, why not just do C - I to get the mat…

Sorry, you did not get it. If the Cartan matrix C is nxn you get n generators which are nxn matrices. The i-th matrix is the identity eye(C) modified as follows: you subtract the i-th line of C from the i-th line of eye(C)

[image] Jean_Michel: The i-th matrix is the identity eye(n) modified as follows: you subtract the i-th line of C from the i-th line of eye(n) I see, so you are really computing G = I - eᵢ*eᵢ'*C = I - eᵢ*C[i,:]' where eᵢ is the unit coordinate vector eᵢ = zeros(n); eᵢ[i]=1. Yes, G = one(C); …

In the above G[i,:] = C[i,:] should be G[i,:] -= C[i,:] I construct other elements of the Coxeter group W by multiplying the generators in various ways — I am not interested only on the action on the vector space.

[image] Jean_Michel: I construct other elements of the Coxeter group W by multiplying the generators in various way — I am not interested only on the action on the vector space. You can probably still improve performance by not constructing the generator matrices explicitly. Multiplying m of…

Yes but in my applications n is small and m is large. For instance, the Weyl group of type E8 has dimension n=8 but cardinality m about 6.0e8

[image] Jean_Michel: Yes but in my applications n is small and m is large. For instance, the Weyl group of type E8 has dimension n=8 but cardinal m about 6.10^8 Then you probably want to store the product explicitly (if you are going to act it on more than n vectors), but you could still gain…

Eye in julia 0.7

New to Julia

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Eye in julia 0.7

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