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Comment by sanderjd | Hacker News Reader

But specifically because of the proprietary compiler? Or is it just calling Fortran / C / C++ libraries that were compiled with their compiler?

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The program is Celeste: https://juliahub.com/case-studies/celeste/index.html

It seems to be pure Julia.

Julia uses the LLVM compiler; I’m pretty sure that’s the only platform, aside from experiments compiling to WASM.

My understanding is that the Julia Petaflops run executed a Julia program per node, communicating via MPI. For some, that's probably obvious/expected for HPC; for others, it might not be considered "pure Julia".

That's how it works in any language on a supercomputer. MPI is pretty much the only game in town for inter-node communication.

@cbkeller: Though MPI is dominant in HPC by a very large margin, it's definitely not the only game in town. SHMEM is an MPI alternative with a smaller but very dedicated following. UPC, Fortran 2008, UPC++, and Chapel are all alternatives that support inter-node communication without relying on MPI or explicit library communication calls. Chapel has the additional advantage of not imposing the SPMD programming model on the user and supporting asynchronous dynamic tasking.

It's my understanding that Julia aspires to join this group of languages if it is able to do so, which is why the Petaflops announcement was originally enticing to me, and then became somewhat less so once I learned that it was relying on MPI.

The compiler is free and open source, not proprietary. It is built on LLVM, which is also FOSS.

And Julia code is not Fortran/C/C++, not sure what you are asking.

The comment I replied to said: "Plus vendor compilers often outperform GCC and LLVM… on Cray systems especially".

I said "Can Julia take advantage of that?". So the "that" in my question was "vendor compilers [which] often outperform GCC and LLVM... on Cray systems especially".

It seems like the answer is, no, Julia cannot be compiled with those vendor compilers that often outperform LLVM.

But it seems that Julia nonetheless has been shown to perform well, just not specifically by using those vendor compilers that I was asking about.

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