using gradf in matlab

To compute numerical gradient for a function in MATLAB, you can use the gradient function.

Syntax:

main.m
[Gx, Gy] = gradient(f)
23 chars
2 lines

where f is the input function, and Gx and Gy are the resulting gradient vectors in the x and y directions, respectively.

For instance, let's say you want to compute the gradient of a 2D Gaussian function:

main.m
[x, y] = meshgrid(-2:.2:2);
f = exp(-x.^2-y.^2);
[Gx, Gy] = gradient(f);
73 chars
4 lines

Here, we use the meshgrid function to generate coordinate matrices x and y, and compute the Gaussian function over the grid based on these coordinates. Then, we use the gradient function to compute the numerical gradient of f in the x and y directions.

Note that you can also specify the grid spacing for x and y as additional arguments to meshgrid, and use the quiver function to visualize the gradient vectors as arrows:

main.m
quiver(x, y, Gx, Gy)
21 chars
2 lines