Hi to all,

I'm doing a simple animation like this:

## ···

--

ion()

x = arange(0,2,0.01)

y = zeros_like(x)

y[45:55]=1

l, = plot(x,y)

D = 0.1

h = x[1]-x[0]

dt = 0.0001;

def nabla(v,h):

na = zeros_like(v)

na[1:-1] = (v[2:]-2*v[1:-1]+v[:-2])

na[0],na[-1] = 0,0

return na/(h**2)

for i in range(1000):

y = y + D*nabla(y,h)*dt

if i%10 == 0:

l.set_ydata(y)

draw()

--

however, changing the line

y = y + D*nabla(y,h)*dt with

in

y += D*nabla(y,h)*dt

the plot is not updated anymore. I have to replace l.set_ydata(y) with

y.recache() to make the the animation work again.

I think this is a bug since the line should be updated even using the

+= operator.

Regards,

Antonio