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+``mdpoly`` or Multidimensional Polynomials
+==========================================
+
+*Work in progress!*
+
+Quick Start
+-----------
+
+There is still a big part of the API missing but the snipped below works enough
+to give an overview.
+
+.. code:: py
+
+ from mdpoly import State, Variable, Parameter
+ from mdpoly.representations import SparseRepr
+
+ # Construct an expression
+ x, y = Variable.from_names("x, y") # or just Variable("x")
+ k = Parameter("k")
+
+ p = (x + 2 * y) ** 3 + y ** 2 + k
+ print(f"{p = }")
+
+ # Expressions can be easily reparametrized
+ w = Parameter("w")
+ q = p.replace(y, w).replace(k, k ** 2) # createas a copy
+ print(f"{q = }")
+
+ # Make a concrete representation
+ state = State(parameters={k: 3.14}) # try to replace with empty dict
+ sparse, state = p.to_repr(SparseRepr, state)
+
+ # Look inside the representation
+ for entry in sparse.entries():
+ print(f"at (row, col) = {entry.row, entry.col} there is a polynomial:")
+ for term in sparse.terms(entry):
+ monomial_str = ""
+ for idx in term:
+ var = state.from_index(idx.var_idx)
+ monomial_str += f"{var.name}^{idx.power} "
+
+ # Get the coefficient
+ coeff = sparse.at(entry, term)
+ print(" - the monomial", monomial_str, "has coefficient", coeff)
+
+ # You can also simply iterate over it
+ for entry, term, coeff in sparse:
+ print(entry, term, coeff)
+
+There is some advanced stuff that is still broken but the idea is that it will
+work soon-ish.
+
+.. code:: py
+
+ from mdpoly import Variable, MatrixVariable
+ from mdpoly.types import Shape
+
+ x = Variable("x")
+ V = MatrixVariable("V", Shape.column(3))
+
+ print(x.shape, V.shape)
+
+ z = x + V # error
+ scalar = V.T @ V # no error (TODO)