diff options
| -rw-r--r-- | polymatrix/denserepr/from_.py | 4 | ||||
| -rw-r--r-- | polymatrix/denserepr/utils/monomialtoindex.py | 15 |
2 files changed, 15 insertions, 4 deletions
diff --git a/polymatrix/denserepr/from_.py b/polymatrix/denserepr/from_.py index 7936c97..1eda6fe 100644 --- a/polymatrix/denserepr/from_.py +++ b/polymatrix/denserepr/from_.py @@ -9,7 +9,7 @@ from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin from polymatrix.expression.utils.getvariableindices import ( get_variable_indices_from_variable, ) -from polymatrix.denserepr.utils.monomialtoindex import variable_indices_to_column_index +from polymatrix.denserepr.utils.monomialtoindex import monomial_to_monomial_vector_indices from polymatrix.denserepr.impl import DenseReprBufferImpl, DenseReprImpl # NP: create a dense representation from a polymatrix expression @@ -150,7 +150,7 @@ def from_polymatrix( # converts (2, 1) to (1, 2) # converts (1, 2) to (3,) # the cols correspond to the column of the dense matrix w.r.t. Z - cols = variable_indices_to_column_index( + cols = monomial_to_monomial_vector_indices( n_param, new_variable_indices ) diff --git a/polymatrix/denserepr/utils/monomialtoindex.py b/polymatrix/denserepr/utils/monomialtoindex.py index a41b9fc..151e8bf 100644 --- a/polymatrix/denserepr/utils/monomialtoindex.py +++ b/polymatrix/denserepr/utils/monomialtoindex.py @@ -2,10 +2,21 @@ import itertools # NP: document this function, especially magic return line -def variable_indices_to_column_index( +def monomial_to_monomial_vector_indices( n_var: int, variable_indices: tuple[int, ...], -) -> int: +) -> set[int]: + """ + Given a monomial of degree d, this function returns the indices of a monomial + vector containing monomial of the same degree. + + Given the variable mapping {x : 0, y : 1}, the monomial x*y of the monomial vector + + z = [x**2 x*y x*y y**2] + + results in indices = (1, 2). + """ + variable_indices_perm = itertools.permutations(variable_indices) return set( |