I tried to investigate this problem more deeply, too. Two arguments call to 'eps' is still fully supported at R2022a!!! The only change is the double quote strings instead of single.

But!!! TMW made a mistake and use in version R2022a some outdated version of 'nthroot' function with single quote at line 35 (nthroot.m) :)

That is all ...

Moreover:
1. R2021b: nthroot.m line 35: m = x ~= 0 & (abs(x) < (1/eps(class(y)))) & isfinite(n);
2. R2022a: nthroot.m line 35: m = x ~= 0 & (abs(x) < 1./eps('like',y)) & isfinite(n);

Thank you for very interesting FFT benchmarks. Especially the MTC parallel scaling is very impressive.

MTC is permanently the best available high-level language solution for multi precision computing. 

I gave up this activity, because I asked for help the Maplesoft and Wolfram support few times to solve some benchmark Maple and Mathematica scripts problems (optimization of the benchmark code to avoid bad programming habits) and the response was very vague or directly unfriendly.

So, sorry for premature promises...:)

OK ... so do you recommend to use your currently available scripts? Can you send me the whole package of all available scripts so that we don't miss anything important?

I am using 8-Core Intel Core i9-9900 with 64GB RAM (Windows 10 Pro).

Pavel, let me know if it is a good idea from your point of view.

Sorry, wrong formulation of my question. I am asking for what precision are presented CPU times?

Of course Pavel, any additional speed up of expm for quadruple precision would be great, especially for me :). I just trying to effectively solve the stiff system of 1st order linear ODEs (constants differ by magnitudes of order), so expm plays crucial role.

The link on new version of MCT does not work. 

403. That’s an error.

We're sorry, but you do not have access to this page. That’s all we know.

I came across YALMIP project (MATLAB optimization environment), and there is REFINER: Built-in layer for arbitrary precision linear programming (https://yalmip.github.io/solver/refiner/), which is based on GEM library (https://github.com/jdbancal/gem), which is of course not so sophisticated as MCT.

Could be possible to create modified version of REFINER based on MCT???

I fully understand your final respond. I expected something like this from the beginning of this discussion.

But, there is still open question: What should MATLAB users do in a case of need to perform any kind of optimization with multi-precision support?

The general recommendation is: use suitable optimization solver in pure MATLAB code and then modify it for MCT. But good optimization solvers are mainly not written in pure MATLAB.

So, situation is really bad for anybody who need to solve optimization problem with multi-precision accuracy.

In my case I am solving linear constrained optimization problem, where constraints are defined by exponential functions of optimized parameters. In MATLAB double class I am reaching always overflow problem.

Any progress on this topic?