diff options
| -rw-r--r-- | mdpoly/types.py | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/mdpoly/types.py b/mdpoly/types.py index 0a4c68e..b580b99 100644 --- a/mdpoly/types.py +++ b/mdpoly/types.py @@ -76,9 +76,17 @@ class PolyVarIndex(NamedTuple): @classmethod @property def constant(cls): - """ Special index for constants, which have no variable """ + """ Special index for constants. + + Constants do not have an associated variable, + and the field power is ignored. + """ return cls(var_idx=-1, power=0) + @staticmethod + def is_constant(index: Self) -> bool: + return index.var_idx == -1 + @classmethod def of_var(cls, variable: Var, state: State, power: Number =1) -> Self: return cls(var_idx=state.index(variable), power=power) @@ -90,17 +98,17 @@ class PolyIndex(tuple[PolyVarIndex]): Example: - Suppose there are two variables x, y with indices 0, 1 respectively. - Then the monomal xy^2 has PolyIndex + Suppose there are two variables x, y with indices 0, 1 respectively (in + the State object). Then the monomal xy^2 has PolyIndex - (PolyVarIndex(varindex=0, power=1), PolyVarIndex(varindex=1, power=2) + (PolyVarIndex(var_idx=0, power=1), PolyVarIndex(var_idx=1, power=2) Then given the polynomial p(x, y) = 3x^2 + 5xy^2 The with the PolyIndex above we can retrieve the coefficient 5 in front - of xy^2. + of xy^2 from the Repr object. """ def __repr__(self) -> str: @@ -112,4 +120,4 @@ class PolyIndex(tuple[PolyVarIndex]): @property def constant(cls): """ Index of the constant term """ - return cls(PolyVarIndex.constant) + return cls((PolyVarIndex.constant,)) |