Hello,
I have a function that accepts and returns a scalar. If I code like this, minres returns an incorrect result, stating that the iteration gave a relative residual of 0:
f = @(x)(x.*x);
b = 10;
res = minres(f, b);
The result changes if I specify an initial guess, otherwise 10 in this case. I was assuming that I'm doing something wrong with function handles, but if b = [10;1;5] for example, the relative residual is evaluated correctly (even though there's no convergence). Any comments, ideas?
I am using version R2011a.
Best regards and thanks in advance
edit: In the meantime, I have found a work-around by shifting the function and using fzero to find the root. fzero isn't mentioned in the doc for any of the iterative solvers or even function handles, sadly, so it took me a few hours to stumble over this command.
I'm leaving the question up because the behavior of the code still seems strange to me.
