Hi all, I have a large sparse matrix A ( its size is (2823,2823 ) its type is SparceMatrixCSC{ Integer, Int64} ) with 0/1 values only. I want to get a sparse matrix B = A^2, and get the largest value in this matrix. For reasons beyond my understanding it looks like matrix B suddenly gets a typ…

[image] Annette_F: A = zeros( Integer, 2400, 2400 ) Do you have a reason for using Integer (an abstract type) here? If you use a concrete type like Int (or BigInt if you need the ability to store arbitrarily large numbers), it will not widen the element type to Any when multiplying.

[image] Annette_F: SparceMatrixCSC{ Integer, Int64} Do you really want the abstract type Integer as the element type, or can you use Int instead?

That’s the type Julia gave to this marix A/compMatrix. (I first initialized a 2-Dim array with only 0/1 values, then converted it to sparse). I don’t really care about Integer or Int. I just want to be able to get matrix B = A^2 and get its max/min. I’m just surprised to see B gets type Any, inst…

Can you share the code you used to make A?

julia> using SparseArrays julia> a = sprand(Int, 7, 7, 0.5) 7×7 SparseMatrixCSC{Int64, Int64} with 25…

It’s based on data, but the following code results in the exact same issues using SparseArrays A = zeros( Integer, 2400, 2400 ) for i in 1:2400 if rand(1:4) == 1 for j in i+1:2400 if rand(1:15) == 1 A[i,j] = 1 A[j,i] = 1 end …

I’m not sure how or what this answers?

As I pointed out, creating the matrix a from Int (concrete type) leads to stable calculation.

Ah, my apologies; I wasn’t aware there was a significant difference between Int and Integer. Indeed the usage of Int solves my problem. Thank you.

I think some of the sparse array code unfortunately relies on inference to compute some things such as the output element type and if the type is abstract, that might widen.

Sparse matrix product causes unnecessary casting to "Any" thereby causing issues?

General Usage

cjdoris July 15, 2021, 8:05am 11

Why is the element type being widened at all? Why doesn’t it stay Integer?

Why is the product of Real and Float64 arrays of eltype Any?

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Sparse matrix product causes unnecessary casting to "Any" thereby causing issues?

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