I've heard that before, usually from people with no experience in actual scientific computing. There's nothing wrong with using functional programming in scientific applications. I do. But I don't see how it's "specifically" good for scientific programming.
The thing about performance in scientific programming, it is often binary: You either need the very best, or you don't care about it at all. Unlike other areas of programming, there is no middle ground. If you need your scientific code to be performant, then you need to squeeze every last bit of performance out of your hardware, which you can only do with something like Fortran or C. If you don't care about performance, then it doesn't matter. That's why Python is so popular.
Ideally I would love for something like F# to replace python in the scientific computing space, but the ecosystem is so much larger in python. That's what matters to most scientists.
Generally agree, but: the idea for FP in scientific computing would be for the FP-optimizing compiler to elide any computation that doesn't contribute to the final result.
The analogy I think of is is tree traversal. A smart person can write an optimal tree traversal algorithm and make their program finish quickly, whether or not the user requested that part of the algorithm's results, but FP can realize the program doesn't output the tree, so traversing it can be skipped. OK, that's not a great analogy but the point is that in principle, FP optimization could find a cheaper way to produce the same exact values as a simulation written in a non-functional language.
The thing about performance in scientific programming, it is often binary: You either need the very best, or you don't care about it at all. Unlike other areas of programming, there is no middle ground. If you need your scientific code to be performant, then you need to squeeze every last bit of performance out of your hardware, which you can only do with something like Fortran or C. If you don't care about performance, then it doesn't matter. That's why Python is so popular.
Ideally I would love for something like F# to replace python in the scientific computing space, but the ecosystem is so much larger in python. That's what matters to most scientists.