Iteration numbers in cminpack

[LittleDogXi]

The parameter "nfev" is the number of fcn calls. But how can I know the iteration numbers using hybrd function?

[luau-project]

According to the user guide for minpack, which can be found at

• Moré, Jorge J., Burton S. Garbow, and Kenneth E. Hillstrom. User guide for MINPACK-1.[In FORTRAN]. No. ANL-80-74. Argonne National Lab.(ANL), Argonne, IL (United States), 1980. DOI: 10.2172/6997568

when you supply the param nprint a positive integer, it enables controlled printing of iterates.

[LittleDogXi]

I set param nprint a postive integer like +1, but I cannot see any printing of iterates in the console. Is the information printed somewhere else?

[luau-project]

I never experimented this nprint param myself, but judging by the docs linked above, I guess you would be called nprint times in the callback or something in that direction.

[LittleDogXi]

I will try it soon later.

[LittleDogXi]

After a few tries, I have figured it out. Set nprint a positive integer, like 1, and add if(*flag==0){std::cout<<"$";} in the fcn function, you could print serval $ characters, which has the same number of iteration times.

[luau-project]

I'm glad that you solved the puzzle.