stm atoc wrote:
Hi there,
I am a new python user.
I have a question regarding do loop.....
This is a simple program that I have written:
-----------------
N=10
h=10.0 # [micrometer]
z=-200.0 # [micrometer]
You define N, h and z here, but later on you use them as loop variables.
So these three values never get used: they are thrown away, and replaced
by the values of the loops:
h -> 0, 1, 2, ... 9
N -> 0, 1, 2, ... 9
z is especially troublesome, because it gets used for TWO loop
variables, one inside the other. The inner z loop depends on the outer z
loop, which makes it tricky to predict what values z will take.
num = 0.05 #m**2/s
dz = 1.0
nuh=[]
tmax=3600
dt=20.
nu=[]height = arange(z*dz,0,dz)
What is arange?
In physics, "height" is a scalar. But later on, you seen to use height
as if it were a collection of values.
outfile=open('nu.dat','w')
outfile.write('height, nu, nuh')
for z,when in enumerate(height):
for h in range(10):
for N in range(10):
for z in range((N-z)+(N-h)):
nuh.append(0.01 * exp(-0.05*(z+200.0))*dz) #turbulence
diffusivity m**2/s
nu.append(num + nuh[z])
-----------------------
What I like to do with this program is do loop like the fortran
version of as follows:
do i = 2, N
z(i) = z(i-1) +h(i-1)
end do
How is z initialised? What is h?
I *think* you are trying to add a small increment to each value, based
on the previous value. Am I close?
Does this example help?
zvalues = [1] # starting value
increments = [0.01, 0.01, 0.02, 0.01, 0.01, 0.02, 0.01, 0.01]
for h in increments:
z = zvalues[-1] + h
zvalues.append(z)
print(zvalues)
(Note: beware of floating point rounding.)
--
Steven
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor
