Unrecognized function or variable 'snopt'. Error in Untitledidk (line 362) [x, f, inform, xmul, fmul] = snopt(xg, xlwr, xupr, xmul, xstate, ... What is this function

% bounds on v-infinity matching (equality) constraint

flow(3) = 0.0;
fupp(3) = 0.0;

flow = flow';
fupp = fupp';

xmul = zeros(3, 1);
xstate = zeros(3, 1);
fmul = zeros(3, 1);
fstate = zeros(3, 1);
% use snopt to find optimal solution

[x, f, inform, xmul, fmul] = snopt(xg, xlwr, xupr, xmul, xstate, ...
    flow, fupp, fmul, fstate, 'fbyfunc');

Answer 1

[G A]

https://github.com/snopt/snopt-matlab

Matlab interface for sparse nonlinear optimization software SNOPT.

Requires the SNOPT software package.