> 
> q[1]:=3;

                              q[1] := 3

> q[2]:=10;

                              q[2] := 10

> n:=2;

                                n := 2

> com:=(x,y)->x+I*y;

                       com := (x, y) -> x + I y

> com(1,2);

                               1 + 2 I

> z[1]:=com(1,1);

                            z[1] := 1 + I

> z[2]:=com(3,2);

                           z[2] := 3 + 2 I

> contourplot(Re(log(com(x,y)-z[1])),x=0..4,y=0..4,grid=[70,70]);

> phi := (z) -> sum(q[i]*log(z-z[i]), i=1..n);

                               n
                             -----
                              \
                 phi := z ->   )   q[i] log(z - z[i])
                              /
                             -----
                             i = 1

> 
> phi(com(1,0));

                   3 ln(1 - 1[1]) + 10 ln(1 - 1[2])

> n;

                                  2

> phi := (u) -> sum(q[i]*log(u-z[i]), i=1..n);

                               n
                             -----
                              \
                 phi := u ->   )   q[i] log(u - z[i])
                              /
                             -----
                             i = 1

> phi(com(1,0));

                     - 3/2 I Pi + 10 ln(-2 - 2 I)

> contourplot(Re(phi(com(x,y))),x=0..4,y=0..4);

> q[1]:=10;

                              q[1] := 10

> contourplot(Re(phi(com(x,y))),x=0..4,y=0..4);

> contourplot(Re(phi(com(x,y))),x=0..4,y=0..4,grid=[50,50]);

>