consider $g$ and $f$ and $h$ as
$ \begin{align*} g(m) &= \begin{cases} 1 & if\;program\;m\;halts\;on\;input\;m \\ 0 & otherwise \\ \end{cases} \end{align*} $
$ \begin{align*} f(m,n) &= \begin{cases} undefined & if\;m=n \\ 1 & if\;program\;m\;halts\;on\;input\;n \\ 0 & otherwise \\ \end{cases} \end{align*} $
$ \begin{align*} h(m,n) &= \begin{cases} 1 & if\;program\;m\;halts\;on\;input\;n \\ 0 & otherwise \\ \end{cases} \end{align*} $
we have a counter example for computability of $g$ and $h$ but we don't have any counter example for $f$ and even more interesting function $f_{all}$ $$f(m,n)=\dfrac{m-n}{m-n}h(m,n)$$ $$f_{all}(m)=1-sgn(\lim_{w \to \infty}\sum_{\substack{n=0 \\ n\neq m}}^{w}(1-f(n,m)))$$
we know that if $p$ is a universal diophantine polynomial then we can represent a non-computable solution to the halting problem as follows $$ h(m,n) = sgn(\lim_{w \to \infty}\sum_{x_1=1}^{w}...\sum_{x_u=1}^{w}\dfrac{1}{1 + wp^2(m,n,x_1,...,x_u)}) $$
now the question is: are $f$ and $f_{all}$ computable?