Corresponding value of a parameter

edit

I don't understand two things. There is no variable x or b in your code. Furthermore, if you run this code what you get is an empty iterator W and a vector w equal to (1,1,...,1)

sage: import itertools
sage: W = itertools.product([0,1], repeat=4)
sage: for w in W: w = vector(w)
sage: W
<itertools.product object at 0x7f5c6f579410>
sage: list(W)
[]
sage: w
(1, 1, 1, 1)
sage: type(w)
<type 'sage.modules.vector_integer_dense.Vector_integer_dense'>

(note that you forgot the line import itertools in your command)

My apologies for ambiguity. I have edited the post. Hope it is now clearer.

the whole code with defined previously matrix A looks like this:

import numpy
import itertools
X = itertools.product([0,1], repeat = n)
results = []
for x in X:
     x = vector(x)
     x = x.row()
     v = x.transpose()
     b = x * A * v
     results.append(b[0, 0])
print results

@Xenia It is much clearer now. I updated my answer below.