from sympy.core.containers import Tuple from sympy.core.function import Function from sympy.core.numbers import oo, Rational from sympy.core.singleton import S from sympy.core.symbol import symbols, Symbol from sympy.functions.combinatorial.numbers import tribonacci, fibonacci from sympy.functions.elementary.exponential import exp from sympy.functions.elementary.miscellaneous import sqrt from sympy.functions.elementary.trigonometric import cos, sin from sympy.series import EmptySequence from sympy.series.sequences import (SeqMul, SeqAdd, SeqPer, SeqFormula, sequence) from sympy.sets.sets import Interval from sympy.tensor.indexed import Indexed, Idx from sympy.series.sequences import SeqExpr, SeqExprOp, RecursiveSeq from sympy.testing.pytest import raises, slow x, y, z = symbols('x y z') n, m = symbols('n m') def test_EmptySequence(): assert S.EmptySequence is EmptySequence assert S.EmptySequence.interval is S.EmptySet assert S.EmptySequence.length is S.Zero assert list(S.EmptySequence) == [] def test_SeqExpr(): #SeqExpr is a baseclass and does not take care of #ensuring all arguments are Basics hence the use of #Tuple(...) here. s = SeqExpr(Tuple(1, n, y), Tuple(x, 0, 10)) assert isinstance(s, SeqExpr) assert s.gen == (1, n, y) assert s.interval == Interval(0, 10) assert s.start == 0 assert s.stop == 10 assert s.length == 11 assert s.variables == (x,) assert SeqExpr(Tuple(1, 2, 3), Tuple(x, 0, oo)).length is oo def test_SeqPer(): s = SeqPer((1, n, 3), (x, 0, 5)) assert isinstance(s, SeqPer) assert s.periodical == Tuple(1, n, 3) assert s.period == 3 assert s.coeff(3) == 1 assert s.free_symbols == {n} assert list(s) == [1, n, 3, 1, n, 3] assert s[:] == [1, n, 3, 1, n, 3] assert SeqPer((1, n, 3), (x, -oo, 0))[0:6] == [1, n, 3, 1, n, 3] raises(ValueError, lambda: SeqPer((1, 2, 3), (0, 1, 2))) raises(ValueError, lambda: SeqPer((1, 2, 3), (x, -oo, oo))) raises(ValueError, lambda: SeqPer(n**2, (0, oo))) assert SeqPer((n, n**2, n**3), (m, 0, oo))[:6] == \ [n, n**2, n**3, n, n**2, n**3] assert SeqPer((n, n**2, n**3), (n, 0, oo))[:6] == [0, 1, 8, 3, 16, 125] assert SeqPer((n, m), (n, 0, oo))[:6] == [0, m, 2, m, 4, m] def test_SeqFormula(): s = SeqFormula(n**2, (n, 0, 5)) assert isinstance(s, SeqFormula) assert s.formula == n**2 assert s.coeff(3) == 9 assert list(s) == [i**2 for i in range(6)] assert s[:] == [i**2 for i in range(6)] assert SeqFormula(n**2, (n, -oo, 0))[0:6] == [i**2 for i in range(6)] assert SeqFormula(n**2, (0, oo)) == SeqFormula(n**2, (n, 0, oo)) assert SeqFormula(n**2, (0, m)).subs(m, x) == SeqFormula(n**2, (0, x)) assert SeqFormula(m*n**2, (n, 0, oo)).subs(m, x) == \ SeqFormula(x*n**2, (n, 0, oo)) raises(ValueError, lambda: SeqFormula(n**2, (0, 1, 2))) raises(ValueError, lambda: SeqFormula(n**2, (n, -oo, oo))) raises(ValueError, lambda: SeqFormula(m*n**2, (0, oo))) seq = SeqFormula(x*(y**2 + z), (z, 1, 100)) assert seq.expand() == SeqFormula(x*y**2 + x*z, (z, 1, 100)) seq = SeqFormula(sin(x*(y**2 + z)),(z, 1, 100)) assert seq.expand(trig=True) == SeqFormula(sin(x*y**2)*cos(x*z) + sin(x*z)*cos(x*y**2), (z, 1, 100)) assert seq.expand() == SeqFormula(sin(x*y**2 + x*z), (z, 1, 100)) assert seq.expand(trig=False) == SeqFormula(sin(x*y**2 + x*z), (z, 1, 100)) seq = SeqFormula(exp(x*(y**2 + z)), (z, 1, 100)) assert seq.expand() == SeqFormula(exp(x*y**2)*exp(x*z), (z, 1, 100)) assert seq.expand(power_exp=False) == SeqFormula(exp(x*y**2 + x*z), (z, 1, 100)) assert seq.expand(mul=False, power_exp=False) == SeqFormula(exp(x*(y**2 + z)), (z, 1, 100)) def test_sequence(): form = SeqFormula(n**2, (n, 0, 5)) per = SeqPer((1, 2, 3), (n, 0, 5)) inter = SeqFormula(n**2) assert sequence(n**2, (n, 0, 5)) == form assert sequence((1, 2, 3), (n, 0, 5)) == per assert sequence(n**2) == inter def test_SeqExprOp(): form = SeqFormula(n**2, (n, 0, 10)) per = SeqPer((1, 2, 3), (m, 5, 10)) s = SeqExprOp(form, per) assert s.gen == (n**2, (1, 2, 3)) assert s.interval == Interval(5, 10) assert s.start == 5 assert s.stop == 10 assert s.length == 6 assert s.variables == (n, m) def test_SeqAdd(): per = SeqPer((1, 2, 3), (n, 0, oo)) form = SeqFormula(n**2) per_bou = SeqPer((1, 2), (n, 1, 5)) form_bou = SeqFormula(n**2, (6, 10)) form_bou2 = SeqFormula(n**2, (1, 5)) assert SeqAdd() == S.EmptySequence assert SeqAdd(S.EmptySequence) == S.EmptySequence assert SeqAdd(per) == per assert SeqAdd(per, S.EmptySequence) == per assert SeqAdd(per_bou, form_bou) == S.EmptySequence s = SeqAdd(per_bou, form_bou2, evaluate=False) assert s.args == (form_bou2, per_bou) assert s[:] == [2, 6, 10, 18, 26] assert list(s) == [2, 6, 10, 18, 26] assert isinstance(SeqAdd(per, per_bou, evaluate=False), SeqAdd) s1 = SeqAdd(per, per_bou) assert isinstance(s1, SeqPer) assert s1 == SeqPer((2, 4, 4, 3, 3, 5), (n, 1, 5)) s2 = SeqAdd(form, form_bou) assert isinstance(s2, SeqFormula) assert s2 == SeqFormula(2*n**2, (6, 10)) assert SeqAdd(form, form_bou, per) == \ SeqAdd(per, SeqFormula(2*n**2, (6, 10))) assert SeqAdd(form, SeqAdd(form_bou, per)) == \ SeqAdd(per, SeqFormula(2*n**2, (6, 10))) assert SeqAdd(per, SeqAdd(form, form_bou), evaluate=False) == \ SeqAdd(per, SeqFormula(2*n**2, (6, 10))) assert SeqAdd(SeqPer((1, 2), (n, 0, oo)), SeqPer((1, 2), (m, 0, oo))) == \ SeqPer((2, 4), (n, 0, oo)) def test_SeqMul(): per = SeqPer((1, 2, 3), (n, 0, oo)) form = SeqFormula(n**2) per_bou = SeqPer((1, 2), (n, 1, 5)) form_bou = SeqFormula(n**2, (n, 6, 10)) form_bou2 = SeqFormula(n**2, (1, 5)) assert SeqMul() == S.EmptySequence assert SeqMul(S.EmptySequence) == S.EmptySequence assert SeqMul(per) == per assert SeqMul(per, S.EmptySequence) == S.EmptySequence assert SeqMul(per_bou, form_bou) == S.EmptySequence s = SeqMul(per_bou, form_bou2, evaluate=False) assert s.args == (form_bou2, per_bou) assert s[:] == [1, 8, 9, 32, 25] assert list(s) == [1, 8, 9, 32, 25] assert isinstance(SeqMul(per, per_bou, evaluate=False), SeqMul) s1 = SeqMul(per, per_bou) assert isinstance(s1, SeqPer) assert s1 == SeqPer((1, 4, 3, 2, 2, 6), (n, 1, 5)) s2 = SeqMul(form, form_bou) assert isinstance(s2, SeqFormula) assert s2 == SeqFormula(n**4, (6, 10)) assert SeqMul(form, form_bou, per) == \ SeqMul(per, SeqFormula(n**4, (6, 10))) assert SeqMul(form, SeqMul(form_bou, per)) == \ SeqMul(per, SeqFormula(n**4, (6, 10))) assert SeqMul(per, SeqMul(form, form_bou2, evaluate=False), evaluate=False) == \ SeqMul(form, per, form_bou2, evaluate=False) assert SeqMul(SeqPer((1, 2), (n, 0, oo)), SeqPer((1, 2), (n, 0, oo))) == \ SeqPer((1, 4), (n, 0, oo)) def test_add(): per = SeqPer((1, 2), (n, 0, oo)) form = SeqFormula(n**2) assert per + (SeqPer((2, 3))) == SeqPer((3, 5), (n, 0, oo)) assert form + SeqFormula(n**3) == SeqFormula(n**2 + n**3) assert per + form == SeqAdd(per, form) raises(TypeError, lambda: per + n) raises(TypeError, lambda: n + per) def test_sub(): per = SeqPer((1, 2), (n, 0, oo)) form = SeqFormula(n**2) assert per - (SeqPer((2, 3))) == SeqPer((-1, -1), (n, 0, oo)) assert form - (SeqFormula(n**3)) == SeqFormula(n**2 - n**3) assert per - form == SeqAdd(per, -form) raises(TypeError, lambda: per - n) raises(TypeError, lambda: n - per) def test_mul__coeff_mul(): assert SeqPer((1, 2), (n, 0, oo)).coeff_mul(2) == SeqPer((2, 4), (n, 0, oo)) assert SeqFormula(n**2).coeff_mul(2) == SeqFormula(2*n**2) assert S.EmptySequence.coeff_mul(100) == S.EmptySequence assert SeqPer((1, 2), (n, 0, oo)) * (SeqPer((2, 3))) == \ SeqPer((2, 6), (n, 0, oo)) assert SeqFormula(n**2) * SeqFormula(n**3) == SeqFormula(n**5) assert S.EmptySequence * SeqFormula(n**2) == S.EmptySequence assert SeqFormula(n**2) * S.EmptySequence == S.EmptySequence raises(TypeError, lambda: sequence(n**2) * n) raises(TypeError, lambda: n * sequence(n**2)) def test_neg(): assert -SeqPer((1, -2), (n, 0, oo)) == SeqPer((-1, 2), (n, 0, oo)) assert -SeqFormula(n**2) == SeqFormula(-n**2) def test_operations(): per = SeqPer((1, 2), (n, 0, oo)) per2 = SeqPer((2, 4), (n, 0, oo)) form = SeqFormula(n**2) form2 = SeqFormula(n**3) assert per + form + form2 == SeqAdd(per, form, form2) assert per + form - form2 == SeqAdd(per, form, -form2) assert per + form - S.EmptySequence == SeqAdd(per, form) assert per + per2 + form == SeqAdd(SeqPer((3, 6), (n, 0, oo)), form) assert S.EmptySequence - per == -per assert form + form == SeqFormula(2*n**2) assert per * form * form2 == SeqMul(per, form, form2) assert form * form == SeqFormula(n**4) assert form * -form == SeqFormula(-n**4) assert form * (per + form2) == SeqMul(form, SeqAdd(per, form2)) assert form * (per + per) == SeqMul(form, per2) assert form.coeff_mul(m) == SeqFormula(m*n**2, (n, 0, oo)) assert per.coeff_mul(m) == SeqPer((m, 2*m), (n, 0, oo)) def test_Idx_limits(): i = symbols('i', cls=Idx) r = Indexed('r', i) assert SeqFormula(r, (i, 0, 5))[:] == [r.subs(i, j) for j in range(6)] assert SeqPer((1, 2), (i, 0, 5))[:] == [1, 2, 1, 2, 1, 2] @slow def test_find_linear_recurrence(): assert sequence((0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55), \ (n, 0, 10)).find_linear_recurrence(11) == [1, 1] assert sequence((1, 2, 4, 7, 28, 128, 582, 2745, 13021, 61699, 292521, \ 1387138), (n, 0, 11)).find_linear_recurrence(12) == [5, -2, 6, -11] assert sequence(x*n**3+y*n, (n, 0, oo)).find_linear_recurrence(10) \ == [4, -6, 4, -1] assert sequence(x**n, (n,0,20)).find_linear_recurrence(21) == [x] assert sequence((1,2,3)).find_linear_recurrence(10, 5) == [0, 0, 1] assert sequence(((1 + sqrt(5))/2)**n + \ (-(1 + sqrt(5))/2)**(-n)).find_linear_recurrence(10) == [1, 1] assert sequence(x*((1 + sqrt(5))/2)**n + y*(-(1 + sqrt(5))/2)**(-n), \ (n,0,oo)).find_linear_recurrence(10) == [1, 1] assert sequence((1,2,3,4,6),(n, 0, 4)).find_linear_recurrence(5) == [] assert sequence((2,3,4,5,6,79),(n, 0, 5)).find_linear_recurrence(6,gfvar=x) \ == ([], None) assert sequence((2,3,4,5,8,30),(n, 0, 5)).find_linear_recurrence(6,gfvar=x) \ == ([Rational(19, 2), -20, Rational(27, 2)], (-31*x**2 + 32*x - 4)/(27*x**3 - 40*x**2 + 19*x -2)) assert sequence(fibonacci(n)).find_linear_recurrence(30,gfvar=x) \ == ([1, 1], -x/(x**2 + x - 1)) assert sequence(tribonacci(n)).find_linear_recurrence(30,gfvar=x) \ == ([1, 1, 1], -x/(x**3 + x**2 + x - 1)) def test_RecursiveSeq(): y = Function('y') n = Symbol('n') fib = RecursiveSeq(y(n - 1) + y(n - 2), y(n), n, [0, 1]) assert fib.coeff(3) == 2