Hello,
The list sage-nt you are using is not the most appropriate for this kind
of question. You would rather use the forum ask.sagemath.org or the
mailing list [email protected] which have larger audience.
Concerning your question, this is because sympy does not like Sage
integers (which are not Python integers). This works fine
sage: from sympy.solvers.diophantine import diop_linear
sage: from sympy.abc import x, y
sage: diop_linear(214866r*x+305900r*y-419336r)
(6650*t - 21595804, -4671*t + 15169024)
Vincent
On 09/10/15 01:40, Helmut Büch wrote:
Trying to solve a linear Diophantine equation with Sage, one gets an error:
sage: from sympy.solvers.diophantine import diop_linear
sage: from sympy.abc import x, y
sage: diop_linear(214866*x+305900*y-419336)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-9-ff311ac80176> in <module>()
----> 1 diop_linear(Integer(214866)*x+Integer(305900)*y-Integer(419336))
/home/hb/Downloads/sage-6.8-x86_64-Linux/local/lib/python2.7/site-packages/sympy/solvers/diophantine.py
in diop_linear(eq, param)
375 diop_general_sum_of_squares()
376 """
--> 377 var, coeff, diop_type = classify_diop(eq)
378
379 if diop_type == "linear":
/home/hb/Downloads/sage-6.8-x86_64-Linux/local/lib/python2.7/site-packages/sympy/solvers/diophantine.py
in classify_diop(eq)
232 ([x, y], {1: 5, x: 1, x**2: 1, y: 0, y**2: 1, x*y: -1},
'binary_quadratic')
233 """
--> 234 eq = eq.expand(force=True)
235 var = list(eq.free_symbols)
236 var.sort(key=default_sort_key)
/home/hb/Downloads/sage-6.8-x86_64-Linux/src/sage/symbolic/expression.pyx in
sage.symbolic.expression.Expression.expand
(/opt/sagemath_tmonteil-debian-wheezy-64/sage-6.8/src/build/cythonized/sage/symbolic/expression.cpp:23858)()
4069 return new_Expression_from_GEx(self._parent,
series_to_poly(self._gobj))
4070
-> 4071 def expand(Expression self, side=None):
4072 """
4073 Expand this symbolic expression. Products of sums and
exponentiated
TypeError: expand() got an unexpected keyword argument 'force'
Doing the same thing in Python3, one gets the correct result:
from sympy.solvers.diophantine import diop_linear
from sympy.abc import x, y
diop_linear(214866*x+305900*y-419336)
(6650*t - 21595804, -4671*t + 15169024)
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