sympy¶

import ampform.sympy

Tools that facilitate in building sympy expressions.

class UnevaluatedExpression(*args: Any, name: Optional[str] = None, **hints: Any)[source]¶

Bases: sympy.core.expr.Expr

Base class for classes that expressions with an evaluate() method.

Derive from this class when decorating a class with implement_expr() or implement_doit_method(). It is important to derive from UnevaluatedExpression, because an evaluate() method has to be implemented.

create_expression(cls: Type[UnevaluatedExpression], *args: Any, evaluate: bool = False, name: Optional[str] = None, **kwargs: Any) → Expr[source]¶

Helper function for implementing Expr.__new__.

See e.g. source code of BlattWeisskopfSquared.

create_symbol_matrix(name: str, m: int, n: int) → MutableDenseMatrix[source]¶

Create a Matrix with symbols as elements.

The MatrixSymbol has some issues when one is interested in the elements of the matrix. This function instead creates a Matrix where the elements are Indexed instances.

To convert these Indexed instances to a Symbol, use symplot.substitute_indexed_symbols().

>>> create_symbol_matrix("A", m=2, n=3)
Matrix([
[A[0, 0], A[0, 1], A[0, 2]],
[A[1, 0], A[1, 1], A[1, 2]]])

implement_doit_method() → Callable[[Type[UnevaluatedExpression]], Type[UnevaluatedExpression]][source]¶

Implement doit() method for an UnevaluatedExpression class.

Implement a doit method for a class that derives from Expr (via UnevaluatedExpression).

implement_expr(n_args: int) → Callable[[Type[UnevaluatedExpression]], Type[UnevaluatedExpression]][source]¶

Decorator for classes that derive from UnevaluatedExpression.

Implement a __new__ and doit method for a class that derives from Expr (via UnevaluatedExpression).

implement_new_method(n_args: int) → Callable[[Type[UnevaluatedExpression]], Type[UnevaluatedExpression]][source]¶

Implement __new__() method for an UnevaluatedExpression class.

Implement a __new__ method for a class that derives from Expr (via UnevaluatedExpression).

AmpForm

sympy¶