示例#1
0
文件: polysys.py 项目: Jerryy/sympy
def solve_biquadratic(f, g, opt):
    """Solve a system of two bivariate quadratic polynomial equations. """
    G = groebner([f, g])

    if len(G) == 1 and G[0].is_ground:
        return None

    if len(G) != 2:
        raise SolveFailed

    p, q = G
    x, y = opt.gens

    p = Poly(p, x, expand=False)
    q = q.ltrim(-1)

    p_roots = [ rcollect(expr, y) for expr in roots(p).keys() ]
    q_roots = roots(q).keys()

    solutions = []

    for q_root in q_roots:
        for p_root in p_roots:
            solution = (p_root.subs(y, q_root), q_root)
            solutions.append(solution)

    return sorted(solutions)
示例#2
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文件: polysys.py 项目: tuhina/sympy
def solve_biquadratic(f, g, opt):
    """Solve a system of two bivariate quadratic polynomial equations. """
    G = groebner([f, g])

    if len(G) == 1 and G[0].is_ground:
        return None

    if len(G) != 2:
        raise SolveFailed

    p, q = G
    x, y = opt.gens

    p = Poly(p, x, expand=False)
    q = q.ltrim(-1)

    p_roots = [ rcollect(expr, y) for expr in roots(p).keys() ]
    q_roots = roots(q).keys()

    solutions = []

    for q_root in q_roots:
        for p_root in p_roots:
            solution = (p_root.subs(y, q_root), q_root)
            solutions.append(solution)

    return sorted(solutions)
示例#3
0
文件: polysys.py 项目: bjodah/sympy
def solve_biquadratic(f, g, opt):
    """Solve a system of two bivariate quadratic polynomial equations.

    Examples
    ========

    >>> from sympy.polys import Options, Poly
    >>> from sympy.abc import x, y
    >>> from sympy.solvers.polysys import solve_biquadratic
    >>> NewOption = Options((x, y), {'domain': 'ZZ'})

    >>> a = Poly(y**2 - 4 + x, y, x, domain='ZZ')
    >>> b = Poly(y*2 + 3*x - 7, y, x, domain='ZZ')
    >>> solve_biquadratic(a, b, NewOption)
    [(1/3, 3), (41/27, 11/9)]

    >>> a = Poly(y + x**2 - 3, y, x, domain='ZZ')
    >>> b = Poly(-y + x - 4, y, x, domain='ZZ')
    >>> solve_biquadratic(a, b, NewOption)
    [(7/2 - sqrt(29)/2, -sqrt(29)/2 - 1/2), (sqrt(29)/2 + 7/2, -1/2 + \
      sqrt(29)/2)]
    """
    G = groebner([f, g])

    if len(G) == 1 and G[0].is_ground:
        return None

    if len(G) != 2:
        raise SolveFailed

    x, y = opt.gens
    p, q = G
    if not p.gcd(q).is_ground:
        # not 0-dimensional
        raise SolveFailed

    p = Poly(p, x, expand=False)
    p_roots = [rcollect(expr, y) for expr in roots(p).keys()]

    q = q.ltrim(-1)
    q_roots = list(roots(q).keys())

    solutions = []

    for q_root in q_roots:
        for p_root in p_roots:
            solution = (p_root.subs(y, q_root), q_root)
            solutions.append(solution)

    return sorted(solutions, key=default_sort_key)
示例#4
0
def solve_biquadratic(f, g, opt):
    """Solve a system of two bivariate quadratic polynomial equations.

    Examples
    ========

    >>> from sympy.polys import Options, Poly
    >>> from sympy.abc import x, y
    >>> from sympy.solvers.polysys import solve_biquadratic
    >>> NewOption = Options((x, y), {'domain': 'ZZ'})

    >>> a = Poly(y**2 - 4 + x, y, x, domain='ZZ')
    >>> b = Poly(y*2 + 3*x - 7, y, x, domain='ZZ')
    >>> solve_biquadratic(a, b, NewOption)
    [(1/3, 3), (41/27, 11/9)]

    >>> a = Poly(y + x**2 - 3, y, x, domain='ZZ')
    >>> b = Poly(-y + x - 4, y, x, domain='ZZ')
    >>> solve_biquadratic(a, b, NewOption)
    [(-sqrt(29)/2 + 7/2, -sqrt(29)/2 - 1/2), (sqrt(29)/2 + 7/2, -1/2 + \
      sqrt(29)/2)]
    """
    G = groebner([f, g])

    if len(G) == 1 and G[0].is_ground:
        return None

    if len(G) != 2:
        raise SolveFailed

    x, y = opt.gens
    p, q = G
    if not p.gcd(q).is_ground:
        # not 0-dimensional
        raise SolveFailed

    p = Poly(p, x, expand=False)
    p_roots = [rcollect(expr, y) for expr in roots(p).keys()]

    q = q.ltrim(-1)
    q_roots = list(roots(q).keys())

    solutions = []

    for q_root in q_roots:
        for p_root in p_roots:
            solution = (p_root.subs(y, q_root), q_root)
            solutions.append(solution)

    return sorted(solutions, key=default_sort_key)
示例#5
0
def solve_biquadratic(f, g, opt):
    """Solve a system of two bivariate quadratic polynomial equations.

    Parameters
    ==========

    f: a single Expr or Poly
        First equation
    g: a single Expr or Poly
        Second Equation
    opt: an Options object
        For specifying keyword arguments and generators

    Returns
    =======

    List[Tuple]
        A List of tuples. Solutions for symbols that satisfy the
        equations listed in seq.

    Examples
    ========

    >>> from sympy import Options, Poly
    >>> from sympy.abc import x, y
    >>> from sympy.solvers.polysys import solve_biquadratic
    >>> NewOption = Options((x, y), {'domain': 'ZZ'})

    >>> a = Poly(y**2 - 4 + x, y, x, domain='ZZ')
    >>> b = Poly(y*2 + 3*x - 7, y, x, domain='ZZ')
    >>> solve_biquadratic(a, b, NewOption)
    [(1/3, 3), (41/27, 11/9)]

    >>> a = Poly(y + x**2 - 3, y, x, domain='ZZ')
    >>> b = Poly(-y + x - 4, y, x, domain='ZZ')
    >>> solve_biquadratic(a, b, NewOption)
    [(7/2 - sqrt(29)/2, -sqrt(29)/2 - 1/2), (sqrt(29)/2 + 7/2, -1/2 + \
      sqrt(29)/2)]
    """
    G = groebner([f, g])

    if len(G) == 1 and G[0].is_ground:
        return None

    if len(G) != 2:
        raise SolveFailed

    x, y = opt.gens
    p, q = G
    if not p.gcd(q).is_ground:
        # not 0-dimensional
        raise SolveFailed

    p = Poly(p, x, expand=False)
    p_roots = [rcollect(expr, y) for expr in roots(p).keys()]

    q = q.ltrim(-1)
    q_roots = list(roots(q).keys())

    solutions = []

    for q_root in q_roots:
        for p_root in p_roots:
            solution = (p_root.subs(y, q_root), q_root)
            solutions.append(solution)

    return sorted(solutions, key=default_sort_key)