GRAD

GRADIENT:

(∇y)(x1i, x2j)=[∂y/∂x1(x1i,x2j), ∂y/∂x2(x1i,x2j)]

HOW TO IMPLEMENT THIS EQUATION

Answer 1

[Fangjun Jiang]

For numerical analysis,

>> help gradient
 GRADIENT Approximate gradient.
    [FX,FY] = GRADIENT(F) returns the numerical gradient of the
    matrix F. FX corresponds to dF/dx, the differences in x (horizontal) 
    direction. FY corresponds to dF/dy, the differences in y (vertical) 
    direction. The spacing between points in each direction is assumed to 
    be one. When F is a vector, DF = GRADIENT(F)is the 1-D gradient.