You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: g_Gaussian.m
    path of file: ./repos/VBA-toolbox/demos/_models
    
    the code of the file until where you have to start completion: function [gx] = g_Gaussian(Xt,P,ut,in)
% Gaussian convolution observation function
% function [gx] = g_Gaussian(Xt,P,ut,in)
% This function evaluates a gaussian-like observation function.
% IN:
%   - Xt: [useless]
%   - P: a 4X1 parameter vector
%   - ut: [useless]
%   - in: input structure. Contains the grid at which to evaluate the
%   gaussian bump gunction
% OUT:
%   - gx: the Gaussian bump function evaluated on the grid.

mu = P(1);
sig = exp(P(2));    % positivity constraint

    
function [gx] = g_Gaussian(Xt,P,ut,in)
% Gaussian convolution observation function
% function [gx] = g_Gaussian(Xt,P,ut,in)
% This function evaluates a gaussian-like observation function.
% IN:
%   - Xt: [useless]
%   - P: a 4X1 parameter vector
%   - ut: [useless]
%   - in: input structure. Contains the grid at which to evaluate the
%   gaussian bump gunction
% OUT:
%   - gx: the Gaussian bump function evaluated on the grid.

mu = P(1);
sig = exp(P(2));    % positivity constraint
A = exp(P(3));      % [id]
k = exp(P(4));
try
    grid = in.grid;
catch
    grid = -100:0.1:100;
end