how to write equation in matlab ?

i want to write a code for the equation attached in file, please help

Answer 1

[Jan]

phi = max(0, 1.5 * pi - ((x - 256).^2 + (y - 256).^2) / 3276.8);

[ajeet verma]

i am interested to draw a plot corresponding to this equation, so what will i have to do?

[Jan]

It depends on how the drawing should look like. What are your inputs?