marcelocb

Almost every time there will be regression test cases to verify the results,and the new builds will never reproduce perfectly the numerical results. In general is not a issue, has to be handled case by case.

A bigger issue is that modern compilers will raise many warnings, and simple inspection will find many bugs, like array or loop boundaries errors, and when you fix the code you get a different result.

Then it has to be handled case by case as well, since you have to check if that affects safety of flight.

I happen to be one of those "real engineers", working in an aerospace company. When I have to re-do some calculations done 30 years ago (yeah, we need to have traceability of calculations for that long and more ... ) , I grab the F77 source code, build with gfortran or Intel Fortran, and believe me, it builds and runs. From Windows workstations to Linux clusters. Easy.

Then I get the python code from 6 months ago, and spend hours figuring the right python version, and library compatibilities ...

And when I read the fortran code, made by (physical stuff) engineers, it is ugly but simple - there is one or maybe two ways to do something. Not the 1000000's of ways of doing the same thing in Python. And I don't have to learn 50 new libraries to understand the code.

By the way, Python has been my language of choice for most stuff in the last 15 years ...