On 11/17/2015 3:51 PM, fl wrote:
n_iter = 50
sz = (n_iter,) # size of array
x = -0.37727
z = np.random.normal(x,0.1,size=sz)
Q = 1e-5 # process variance
# allocate space for arrays
xhat=np.zeros(sz)
P=np.zeros(sz)
I learn Python now and the above code seems from an experienced author.
The curious thing to me is the variable 'sz'.
'sz' is a name and in the program above, it is a constant tuple derived
from constant int n_iter. Since the tuple is used more than once,
calculating it just once and naming it is a good idea.
> I have check np.zeros(shape, ..)
Reading about the the signature of functions that you use or read about
is a good idea and quite normal.
shape : int or sequence of ints
The introduced 'sz' is a tuple.
and tuples are sequences.
> If n_iter function is similar to a constant in C,
n_iter is a named constant, not a function, as you note below.
> I don't see the reason for 'sz'.
I gave a reason for it existig above, but I think you are asking about
its use in the particular location.
In fact, 'n_iter' is an int, which fits the below
np.zeros(shape)
correctly. Could you see something useful with variable 'sz'?
I would presume until I tried it that np.zeros(50) and np.zeros((50,))
are different (have a different shape). If they are not, then the use
of a singleton tuple is confusing, whether or not the tuple is given a name.
--
Terry Jan Reedy
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