Same problem, same Matlab, different answers

I am running Matlab 2018b on several computers. The problem I am using is (the badly conditioned) > inv(hilb(6)) All computers except my new Lenovo produce the same answer. My new Lenovo X1 gives results that differ in the last 5 double precision digits, i.e. the first 10 are the same as before. The processors are i5-8350U (New Lenovo X1), Intel i7-3820 (older computer), Ryzen 7 (latest). Only Lenovo gives different result. Has anyone seen this?

Answer 1

[the cyclist]

Hazy memories here, but I think even the same processor can have a different BLAS.

[Walter Roberson]

Or different Intel MKL (Math Kernel Library)

By the way, is there a difference in OS version?

It would not have surprised me if the Ryzen had produced a different answer, as it is AMD rather than Intel.

[David Jeffrey]

Is there a way to find out what BLAS or MKL is being used? The two Intel chips are running the same version of Windows 10 and the same Matlab 9.5. The Ryzen, which gave exactly the same answers as all Windows-64 Matlabs was running Linux, I think. Does Matlab include BLAS code in its compile, or does it get it from the operating system?

[Walter Roberson]

MATLAB generally includes libblas but not necessarily the same version for all platforms.

For Mac it is bin/maci64/libmwblas.dylib and bin/maci64/mkl.dylib and there is also bin/maci64/libmwlapack.dylib which is relevant because lapack is the matrix algebra library