Thanks Joe for the comment.
Actually that was just a stupid choice of sub-region that I left at the
end of my testing.
The same problem is present if instead of the condition
if abs(x) < r1 and abs(y) < r1:
one uses
if abs(x) < 2 and abs(y) < 2:
or any similar small region /entirely/ included in the ring.
Sorry for the useless extra-mistake that has misled already some people.
Best,
Diego
On 24/3/14 11:47 PM, Joseph Weston wrote:
Hi,
Seems to me that in your onsite function::
def mu(site, p):
(x, y) = site.pos
if abs(x) < r1 and abs(y) < r1:
return p.mu_inside # this is the critical line: changing
mu values inside the ring should not change the ring conductance
else:
return p.mu_ring
the condition ``abs(x) < r1 and abs(y) < r1`` actually describes a
*square* centred on (0, 0) with sides of length ``2 * r1``, and **not**
a circle centred on (0, 0) with radius ``r1``. There are thus some
sites at the corners which are included in this square, the onsites
of which are affected when you change the value of ``mu_inside``.
Changing the onsite function to the following should fix your problem::
def mu(site, p):
(x, y) = site.pos
if x**2 + y**2 < r1**2:
return p.mu_inside # this is the critical line: changing
mu values inside the ring should not change the ring conductance
else:
return p.mu_ring
Regards,
Joe
P.S. I have not tested the above code. You may need to change your
shape function to::
def ring(pos):
(x, y) = pos
rsq = x ** 2 + y ** 2
return (r1 ** 2 <= rsq < r2 ** 2) # changed `<` to `<=`
to avoid some possible annoying edge case
