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# local variable 'Integer' referenced before assignment Anonymous

I'll be honest I have no idea why this error is popping up, and it's really weird! I'm writing code that will generate a closed form solution to the partial sums of integer powers up to n, and this is what I have

def sum_first_n_p_powers(p):
length = p+1
vector = zero_vector(length)
matrix_list = []
for x in xrange(0,length):
copy = vector[:]
for y in xrange(0,length):
copy[y] = binomial(length-y,x-y+1)
matrix_list.append(copy)
M = Matrix(matrix_list)
solution_vector = zero_vector(length)
solution_vector = 1
coeffs = M.solve_right(solution_vector)
n = var('n')
0 = polynomial
for x in xrange(0,len(coeffs)):
polynomial = polynomial + coeffs[x]*n^(length-x)
return polynomial


And when I try to run it I get the most unusual error, it just says to me

UnboundLocalError: local variable 'Integer' referenced before assignment. I have never run into this before and have no idea what's wrong with the line. Thanks in advance!

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## 1 Answer

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Try this change:

    polynomial = 0


Seems to do what you want then; naturally 0 = polynomial is not valid Python in any case.

I don't know how that even got through the preparser without a worse error indicating what you did wrong more obviously - I have submitted Trac 24971 regarding this very subtle thing, which seems to be a double preparsing of Sage stuff in this case.

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Asked: 2018-03-14 02:12:23 +0200

Seen: 799 times

Last updated: Mar 14 '18