def plot_implicit( expr, x_var=None, y_var=None, adaptive=True, depth=0, points=300, line_color="blue", show=True, **kwargs ): """A plot function to plot implicit equations / inequalities. Arguments ========= - ``expr`` : The equation / inequality that is to be plotted. - ``x_var`` (optional) : symbol to plot on x-axis or tuple giving symbol and range as ``(symbol, xmin, xmax)`` - ``y_var`` (optional) : symbol to plot on y-axis or tuple giving symbol and range as ``(symbol, ymin, ymax)`` If neither ``x_var`` nor ``y_var`` are given then the free symbols in the expression will be assigned in the order they are sorted. The following keyword arguments can also be used: - ``adaptive`` Boolean. The default value is set to True. It has to be set to False if you want to use a mesh grid. - ``depth`` integer. The depth of recursion for adaptive mesh grid. Default value is 0. Takes value in the range (0, 4). - ``points`` integer. The number of points if adaptive mesh grid is not used. Default value is 300. - ``show`` Boolean. Default value is True. If set to False, the plot will not be shown. See ``Plot`` for further information. - ``title`` string. The title for the plot. - ``xlabel`` string. The label for the x-axis - ``ylabel`` string. The label for the y-axis Aesthetics options: - ``line_color``: float or string. Specifies the color for the plot. See ``Plot`` to see how to set color for the plots. Default value is "Blue" plot_implicit, by default, uses interval arithmetic to plot functions. If the expression cannot be plotted using interval arithmetic, it defaults to a generating a contour using a mesh grid of fixed number of points. By setting adaptive to False, you can force plot_implicit to use the mesh grid. The mesh grid method can be effective when adaptive plotting using interval arithmetic, fails to plot with small line width. Examples ======== Plot expressions: >>> from sympy import plot_implicit, cos, sin, symbols, Eq, And >>> x, y = symbols('x y') Without any ranges for the symbols in the expression >>> p1 = plot_implicit(Eq(x**2 + y**2, 5)) With the range for the symbols >>> p2 = plot_implicit(Eq(x**2 + y**2, 3), ... (x, -3, 3), (y, -3, 3)) With depth of recursion as argument. >>> p3 = plot_implicit(Eq(x**2 + y**2, 5), ... (x, -4, 4), (y, -4, 4), depth = 2) Using mesh grid and not using adaptive meshing. >>> p4 = plot_implicit(Eq(x**2 + y**2, 5), ... (x, -5, 5), (y, -2, 2), adaptive=False) Using mesh grid with number of points as input. >>> p5 = plot_implicit(Eq(x**2 + y**2, 5), ... (x, -5, 5), (y, -2, 2), ... adaptive=False, points=400) Plotting regions. >>> p6 = plot_implicit(y > x**2) Plotting Using boolean conjunctions. >>> p7 = plot_implicit(And(y > x, y > -x)) When plotting an expression with a single variable (y - 1, for example), specify the x or the y variable explicitly: >>> p8 = plot_implicit(y - 1, y_var=y) >>> p9 = plot_implicit(x - 1, x_var=x) """ has_equality = False # Represents whether the expression contains an Equality, # GreaterThan or LessThan def arg_expand(bool_expr): """ Recursively expands the arguments of an Boolean Function """ for arg in bool_expr.args: if isinstance(arg, BooleanFunction): arg_expand(arg) elif isinstance(arg, Relational): arg_list.append(arg) arg_list = [] if isinstance(expr, BooleanFunction): arg_expand(expr) # Check whether there is an equality in the expression provided. if any(isinstance(e, (Equality, GreaterThan, LessThan)) for e in arg_list): has_equality = True elif not isinstance(expr, Relational): expr = Eq(expr, 0) has_equality = True elif isinstance(expr, (Equality, GreaterThan, LessThan)): has_equality = True xyvar = [i for i in (x_var, y_var) if i is not None] free_symbols = expr.free_symbols range_symbols = Tuple(*flatten(xyvar)).free_symbols undeclared = free_symbols - range_symbols if len(free_symbols & range_symbols) > 2: raise NotImplementedError( "Implicit plotting is not implemented for " "more than 2 variables" ) # Create default ranges if the range is not provided. default_range = Tuple(-5, 5) def _range_tuple(s): if isinstance(s, Symbol): return Tuple(s) + default_range if len(s) == 3: return Tuple(*s) raise ValueError("symbol or `(symbol, min, max)` expected but got %s" % s) if len(xyvar) == 0: xyvar = list(_sort_gens(free_symbols)) var_start_end_x = _range_tuple(xyvar[0]) x = var_start_end_x[0] if len(xyvar) != 2: if x in undeclared or not undeclared: xyvar.append(Dummy("f(%s)" % x.name)) else: xyvar.append(undeclared.pop()) var_start_end_y = _range_tuple(xyvar[1]) # Check whether the depth is greater than 4 or less than 0. if depth > 4: depth = 4 elif depth < 0: depth = 0 series_argument = ImplicitSeries( expr, var_start_end_x, var_start_end_y, has_equality, adaptive, depth, points, line_color, ) # set the x and y limits kwargs["xlim"] = tuple(float(x) for x in var_start_end_x[1:]) kwargs["ylim"] = tuple(float(y) for y in var_start_end_y[1:]) # set the x and y labels kwargs.setdefault("xlabel", var_start_end_x[0].name) kwargs.setdefault("ylabel", var_start_end_y[0].name) p = Plot(series_argument, **kwargs) if show: p.show() return p
def test__sort_gens(): assert _sort_gens([]) == () assert _sort_gens([x]) == (x,) assert _sort_gens([p]) == (p,) assert _sort_gens([q]) == (q,) assert _sort_gens([x, p]) == (x, p) assert _sort_gens([p, x]) == (x, p) assert _sort_gens([q, p]) == (p, q) assert _sort_gens([q, p, x]) == (x, p, q) assert _sort_gens([x, p, q], wrt=x) == (x, p, q) assert _sort_gens([x, p, q], wrt=p) == (p, x, q) assert _sort_gens([x, p, q], wrt=q) == (q, x, p) assert _sort_gens([x, p, q], wrt='x') == (x, p, q) assert _sort_gens([x, p, q], wrt='p') == (p, x, q) assert _sort_gens([x, p, q], wrt='q') == (q, x, p) assert _sort_gens([x, p, q], wrt='x,q') == (x, q, p) assert _sort_gens([x, p, q], wrt='q,x') == (q, x, p) assert _sort_gens([x, p, q], wrt='p,q') == (p, q, x) assert _sort_gens([x, p, q], wrt='q,p') == (q, p, x) assert _sort_gens([x, p, q], wrt='x, q') == (x, q, p) assert _sort_gens([x, p, q], wrt='q, x') == (q, x, p) assert _sort_gens([x, p, q], wrt='p, q') == (p, q, x) assert _sort_gens([x, p, q], wrt='q, p') == (q, p, x) assert _sort_gens([x, p, q], wrt=[x, 'q']) == (x, q, p) assert _sort_gens([x, p, q], wrt=[q, 'x']) == (q, x, p) assert _sort_gens([x, p, q], wrt=[p, 'q']) == (p, q, x) assert _sort_gens([x, p, q], wrt=[q, 'p']) == (q, p, x) assert _sort_gens([x, p, q], wrt=['x', 'q']) == (x, q, p) assert _sort_gens([x, p, q], wrt=['q', 'x']) == (q, x, p) assert _sort_gens([x, p, q], wrt=['p', 'q']) == (p, q, x) assert _sort_gens([x, p, q], wrt=['q', 'p']) == (q, p, x) assert _sort_gens([x, p, q], sort='x > p > q') == (x, p, q) assert _sort_gens([x, p, q], sort='p > x > q') == (p, x, q) assert _sort_gens([x, p, q], sort='p > q > x') == (p, q, x) assert _sort_gens([x, p, q], wrt='x', sort='q > p') == (x, q, p) assert _sort_gens([x, p, q], wrt='p', sort='q > x') == (p, q, x) assert _sort_gens([x, p, q], wrt='q', sort='p > x') == (q, p, x) # https://github.com/sympy/sympy/issues/19353 n1 = Symbol('\n1') assert _sort_gens([n1]) == (n1,) assert _sort_gens([x, n1]) == (x, n1) X = symbols('x0,x1,x2,x10,x11,x12,x20,x21,x22') assert _sort_gens(X) == X
def plot_implicit(expr, x_var=None, y_var=None, **kwargs): """A plot function to plot implicit equations / inequalities. Arguments ========= - ``expr`` : The equation / inequality that is to be plotted. - ``x_var`` (optional) : symbol to plot on x-axis or tuple giving symbol and range as ``(symbol, xmin, xmax)`` - ``y_var`` (optional) : symbol to plot on y-axis or tuple giving symbol and range as ``(symbol, ymin, ymax)`` If neither ``x_var`` nor ``y_var`` are given then the free symbols in the expression will be assigned in the order they are sorted. The following keyword arguments can also be used: - ``adaptive``. Boolean. The default value is set to True. It has to be set to False if you want to use a mesh grid. - ``depth`` integer. The depth of recursion for adaptive mesh grid. Default value is 0. Takes value in the range (0, 4). - ``points`` integer. The number of points if adaptive mesh grid is not used. Default value is 200. - ``title`` string .The title for the plot. - ``xlabel`` string. The label for the x-axis - ``ylabel`` string. The label for the y-axis plot_implicit, by default, uses interval arithmetic to plot functions. If the expression cannot be plotted using interval arithmetic, it defaults to a generating a contour using a mesh grid of fixed number of points. By setting adaptive to False, you can force plot_implicit to use the mesh grid. The mesh grid method can be effective when adaptive plotting using interval arithmetic, fails to plot with small line width. Examples: ========= Plot expressions: >>> from sympy import plot_implicit, cos, sin, symbols, Eq, And >>> x, y = symbols('x y') Without any ranges for the symbols in the expression >>> p1 = plot_implicit(Eq(x**2 + y**2, 5)) With the range for the symbols >>> p2 = plot_implicit(Eq(x**2 + y**2, 3), ... (x, -3, 3), (y, -3, 3)) With depth of recursion as argument. >>> p3 = plot_implicit(Eq(x**2 + y**2, 5), ... (x, -4, 4), (y, -4, 4), depth = 2) Using mesh grid and not using adaptive meshing. >>> p4 = plot_implicit(Eq(x**2 + y**2, 5), ... (x, -5, 5), (y, -2, 2), adaptive=False) Using mesh grid with number of points as input. >>> p5 = plot_implicit(Eq(x**2 + y**2, 5), ... (x, -5, 5), (y, -2, 2), ... adaptive=False, points=400) Plotting regions. >>> p6 = plot_implicit(y > x**2) Plotting Using boolean conjunctions. >>> p7 = plot_implicit(And(y > x, y > -x)) """ has_equality = False # Represents whether the expression contains an Equality, # GreaterThan or LessThan def arg_expand(bool_expr): """ Recursively expands the arguments of an Boolean Function """ for arg in bool_expr.args: if isinstance(arg, BooleanFunction): arg_expand(arg) elif isinstance(arg, Relational): arg_list.append(arg) arg_list = [] if isinstance(expr, BooleanFunction): arg_expand(expr) # Check whether there is an equality in the expression provided. if any(isinstance(e, (Equality, GreaterThan, LessThan)) for e in arg_list): has_equality = True elif not isinstance(expr, Relational): expr = Eq(expr, 0) has_equality = True elif isinstance(expr, (Equality, GreaterThan, LessThan)): has_equality = True xyvar = [i for i in (x_var, y_var) if i is not None] free_symbols = expr.free_symbols range_symbols = Tuple(*flatten(xyvar)).free_symbols undeclared = free_symbols - range_symbols if len(free_symbols & range_symbols) > 2: raise NotImplementedError("Implicit plotting is not implemented for " "more than 2 variables") # Create default ranges if the range is not provided. default_range = Tuple(-5, 5) def _range_tuple(s): if isinstance(s, Symbol): return Tuple(s) + default_range if len(s) == 3: return Tuple(*s) raise ValueError("symbol or `(symbol, min, max)` expected but got %s" % s) if len(xyvar) == 0: xyvar = list(_sort_gens(free_symbols)) var_start_end_x = _range_tuple(xyvar[0]) x = var_start_end_x[0] if len(xyvar) != 2: if x in undeclared or not undeclared: xyvar.append(Dummy("f(%s)" % x.name)) else: xyvar.append(undeclared.pop()) var_start_end_y = _range_tuple(xyvar[1]) use_interval = kwargs.pop("adaptive", True) nb_of_points = kwargs.pop("points", 300) depth = kwargs.pop("depth", 0) # Check whether the depth is greater than 4 or less than 0. if depth > 4: depth = 4 elif depth < 0: depth = 0 series_argument = ImplicitSeries( expr, var_start_end_x, var_start_end_y, has_equality, use_interval, depth, nb_of_points ) show = kwargs.pop("show", True) # set the x and y limits kwargs["xlim"] = tuple(float(x) for x in var_start_end_x[1:]) kwargs["ylim"] = tuple(float(y) for y in var_start_end_y[1:]) # set the x and y labels kwargs.setdefault("xlabel", var_start_end_x[0].name) kwargs.setdefault("ylabel", var_start_end_y[0].name) p = Plot(series_argument, **kwargs) if show: p.show() return p
def test__sort_gens(): assert _sort_gens([]) == () assert _sort_gens([x]) == (x, ) assert _sort_gens([p]) == (p, ) assert _sort_gens([q]) == (q, ) assert _sort_gens([x, p]) == (x, p) assert _sort_gens([p, x]) == (x, p) assert _sort_gens([q, p]) == (p, q) assert _sort_gens([q, p, x]) == (x, p, q) assert _sort_gens([x, p, q], wrt=x) == (x, p, q) assert _sort_gens([x, p, q], wrt=p) == (p, x, q) assert _sort_gens([x, p, q], wrt=q) == (q, x, p) assert _sort_gens([x, p, q], wrt='x') == (x, p, q) assert _sort_gens([x, p, q], wrt='p') == (p, x, q) assert _sort_gens([x, p, q], wrt='q') == (q, x, p) assert _sort_gens([x, p, q], wrt='x,q') == (x, q, p) assert _sort_gens([x, p, q], wrt='q,x') == (q, x, p) assert _sort_gens([x, p, q], wrt='p,q') == (p, q, x) assert _sort_gens([x, p, q], wrt='q,p') == (q, p, x) assert _sort_gens([x, p, q], wrt='x, q') == (x, q, p) assert _sort_gens([x, p, q], wrt='q, x') == (q, x, p) assert _sort_gens([x, p, q], wrt='p, q') == (p, q, x) assert _sort_gens([x, p, q], wrt='q, p') == (q, p, x) assert _sort_gens([x, p, q], wrt=[x, 'q']) == (x, q, p) assert _sort_gens([x, p, q], wrt=[q, 'x']) == (q, x, p) assert _sort_gens([x, p, q], wrt=[p, 'q']) == (p, q, x) assert _sort_gens([x, p, q], wrt=[q, 'p']) == (q, p, x) assert _sort_gens([x, p, q], wrt=['x', 'q']) == (x, q, p) assert _sort_gens([x, p, q], wrt=['q', 'x']) == (q, x, p) assert _sort_gens([x, p, q], wrt=['p', 'q']) == (p, q, x) assert _sort_gens([x, p, q], wrt=['q', 'p']) == (q, p, x) assert _sort_gens([x, p, q], sort='x > p > q') == (x, p, q) assert _sort_gens([x, p, q], sort='p > x > q') == (p, x, q) assert _sort_gens([x, p, q], sort='p > q > x') == (p, q, x) assert _sort_gens([x, p, q], wrt='x', sort='q > p') == (x, q, p) assert _sort_gens([x, p, q], wrt='p', sort='q > x') == (p, q, x) assert _sort_gens([x, p, q], wrt='q', sort='p > x') == (q, p, x) X = symbols('x0,x1,x2,x10,x11,x12,x20,x21,x22') assert _sort_gens(X) == X
def test__sort_gens(): assert _sort_gens([]) == () assert _sort_gens([x]) == (x,) assert _sort_gens([p]) == (p,) assert _sort_gens([q]) == (q,) assert _sort_gens([x, p]) == (x, p) assert _sort_gens([p, x]) == (x, p) assert _sort_gens([q, p]) == (p, q) assert _sort_gens([q, p, x]) == (x, p, q) assert _sort_gens([x, p, q], wrt=x) == (x, p, q) assert _sort_gens([x, p, q], wrt=p) == (p, x, q) assert _sort_gens([x, p, q], wrt=q) == (q, x, p) assert _sort_gens([x, p, q], wrt='x') == (x, p, q) assert _sort_gens([x, p, q], wrt='p') == (p, x, q) assert _sort_gens([x, p, q], wrt='q') == (q, x, p) assert _sort_gens([x, p, q], wrt='x,q') == (x, q, p) assert _sort_gens([x, p, q], wrt='q,x') == (q, x, p) assert _sort_gens([x, p, q], wrt='p,q') == (p, q, x) assert _sort_gens([x, p, q], wrt='q,p') == (q, p, x) assert _sort_gens([x, p, q], wrt='x, q') == (x, q, p) assert _sort_gens([x, p, q], wrt='q, x') == (q, x, p) assert _sort_gens([x, p, q], wrt='p, q') == (p, q, x) assert _sort_gens([x, p, q], wrt='q, p') == (q, p, x) assert _sort_gens([x, p, q], wrt=[x, 'q']) == (x, q, p) assert _sort_gens([x, p, q], wrt=[q, 'x']) == (q, x, p) assert _sort_gens([x, p, q], wrt=[p, 'q']) == (p, q, x) assert _sort_gens([x, p, q], wrt=[q, 'p']) == (q, p, x) assert _sort_gens([x, p, q], wrt=['x', 'q']) == (x, q, p) assert _sort_gens([x, p, q], wrt=['q', 'x']) == (q, x, p) assert _sort_gens([x, p, q], wrt=['p', 'q']) == (p, q, x) assert _sort_gens([x, p, q], wrt=['q', 'p']) == (q, p, x) assert _sort_gens([x, p, q], sort='x > p > q') == (x, p, q) assert _sort_gens([x, p, q], sort='p > x > q') == (p, x, q) assert _sort_gens([x, p, q], sort='p > q > x') == (p, q, x) assert _sort_gens([x, p, q], wrt='x', sort='q > p') == (x, q, p) assert _sort_gens([x, p, q], wrt='p', sort='q > x') == (p, q, x) assert _sort_gens([x, p, q], wrt='q', sort='p > x') == (q, p, x) X = symbols('x0,x1,x2,x10,x11,x12,x20,x21,x22') assert _sort_gens(X) == X
def test__sort_gens(): assert _sort_gens([]) == () assert _sort_gens([x]) == (x, ) assert _sort_gens([p]) == (p, ) assert _sort_gens([q]) == (q, ) assert _sort_gens([x, p]) == (x, p) assert _sort_gens([p, x]) == (x, p) assert _sort_gens([q, p]) == (p, q) assert _sort_gens([q, p, x]) == (x, p, q) assert _sort_gens([x, p, q], wrt='x') == (x, p, q) assert _sort_gens([x, p, q], wrt='p') == (p, x, q) assert _sort_gens([x, p, q], wrt='q') == (q, x, p) assert _sort_gens([x, p, q], sort='x < p < q') == (x, p, q) assert _sort_gens([x, p, q], sort='p < x < q') == (p, x, q) assert _sort_gens([x, p, q], sort='p < q < x') == (p, q, x) assert _sort_gens([x, p, q], wrt='x', sort='q < p') == (x, q, p) assert _sort_gens([x, p, q], wrt='p', sort='q < x') == (p, q, x) assert _sort_gens([x, p, q], wrt='q', sort='p < x') == (q, p, x)
def test__sort_gens(): assert _sort_gens([]) == () assert _sort_gens([x]) == (x,) assert _sort_gens([p]) == (p,) assert _sort_gens([q]) == (q,) assert _sort_gens([x,p]) == (x,p) assert _sort_gens([p,x]) == (x,p) assert _sort_gens([q,p]) == (p,q) assert _sort_gens([q,p,x]) == (x,p,q) assert _sort_gens([x,p,q], wrt='x') == (x,p,q) assert _sort_gens([x,p,q], wrt='p') == (p,x,q) assert _sort_gens([x,p,q], wrt='q') == (q,x,p) assert _sort_gens([x,p,q], sort='x < p < q') == (x, p, q) assert _sort_gens([x,p,q], sort='p < x < q') == (p, x, q) assert _sort_gens([x,p,q], sort='p < q < x') == (p, q, x) assert _sort_gens([x,p,q], wrt='x', sort='q < p') == (x, q, p) assert _sort_gens([x,p,q], wrt='p', sort='q < x') == (p, q, x) assert _sort_gens([x,p,q], wrt='q', sort='p < x') == (q, p, x)
def test__sort_gens(): assert _sort_gens([]) == () assert _sort_gens([x]) == (x, ) assert _sort_gens([p]) == (p, ) assert _sort_gens([q]) == (q, ) assert _sort_gens([x, p]) == (x, p) assert _sort_gens([p, x]) == (x, p) assert _sort_gens([q, p]) == (p, q) assert _sort_gens([q, p, x]) == (x, p, q) assert _sort_gens([x, p, q], wrt=x) == (x, p, q) assert _sort_gens([x, p, q], wrt=p) == (p, x, q) assert _sort_gens([x, p, q], wrt=q) == (q, x, p) assert _sort_gens([x, p, q], wrt="x") == (x, p, q) assert _sort_gens([x, p, q], wrt="p") == (p, x, q) assert _sort_gens([x, p, q], wrt="q") == (q, x, p) assert _sort_gens([x, p, q], wrt="x,q") == (x, q, p) assert _sort_gens([x, p, q], wrt="q,x") == (q, x, p) assert _sort_gens([x, p, q], wrt="p,q") == (p, q, x) assert _sort_gens([x, p, q], wrt="q,p") == (q, p, x) assert _sort_gens([x, p, q], wrt="x, q") == (x, q, p) assert _sort_gens([x, p, q], wrt="q, x") == (q, x, p) assert _sort_gens([x, p, q], wrt="p, q") == (p, q, x) assert _sort_gens([x, p, q], wrt="q, p") == (q, p, x) assert _sort_gens([x, p, q], wrt=[x, "q"]) == (x, q, p) assert _sort_gens([x, p, q], wrt=[q, "x"]) == (q, x, p) assert _sort_gens([x, p, q], wrt=[p, "q"]) == (p, q, x) assert _sort_gens([x, p, q], wrt=[q, "p"]) == (q, p, x) assert _sort_gens([x, p, q], wrt=["x", "q"]) == (x, q, p) assert _sort_gens([x, p, q], wrt=["q", "x"]) == (q, x, p) assert _sort_gens([x, p, q], wrt=["p", "q"]) == (p, q, x) assert _sort_gens([x, p, q], wrt=["q", "p"]) == (q, p, x) assert _sort_gens([x, p, q], sort="x > p > q") == (x, p, q) assert _sort_gens([x, p, q], sort="p > x > q") == (p, x, q) assert _sort_gens([x, p, q], sort="p > q > x") == (p, q, x) assert _sort_gens([x, p, q], wrt="x", sort="q > p") == (x, q, p) assert _sort_gens([x, p, q], wrt="p", sort="q > x") == (p, q, x) assert _sort_gens([x, p, q], wrt="q", sort="p > x") == (q, p, x) X = symbols("x0,x1,x2,x10,x11,x12,x20,x21,x22") assert _sort_gens(X) == X