Matlab computes radians from -pi to pi instead of 0 to 2pi

Question

I am working on a problem where the pressure profile should be smooth. For this, the angle should be from 0to 2pi. But when I take the logarithm of some complex numbers, MATLAB displays the angle in piin the negative range pi(clockwise).

For instance:

var_z = [20.0 + 0.6i,  20.0 - 0.6i];
za2 = -2.5000 + 0.5000i;
A = log (-(var_z-za2))   

gives A = [3.11 - 3.13i, 3.11 + 3.091i], but if the angle was only in the counterclockwise direction (i.e. [0, 2pi]), we would get [3.11 + 3.14i, 3.11 + 3.09i].

The latter result makes more sense in my situation, since it prevents the quick jump of pressure profiles. Is there any way to get MATLAB to use 0to 2pito radians?

Answer 1

log :

log(abs(z)) + 1i*angle(z)

, "" , 2π-, log:

log(abs(z)) + 1i*mod(angle(z),2*pi)

, :

l = @(z)log(abs(z)) + 1i*mod(angle(z),2*pi);

>> log(-([20.0 + 0.6i,  20.0 - 0.6i]-(-2.5000 + 0.5000i)))

ans =

   3.1135 - 3.1371i   3.1147 + 3.0927i

>> l(-([20.0 + 0.6i,  20.0 - 0.6i]-(-2.5000 + 0.5000i)))

ans =

   3.1135 + 3.1460i   3.1147 + 3.0927i

... , .

Answer 2

0 2pi:

f(x,y)=pi()-pi()/2*(1+sign(x))*(1-sign(y^2))-pi()/4*(2+sign(x))*sign(y)
       -sign(x*y)*atan((abs(x)-abs(y))/(abs(x)+abs(y)))