Class Table

ar.py:273–523

The coefficient matrix.

class Table:
  """The coefficient matrix."""

  def __init__(self, const: str = '1'):
    self.const = const
    self.v2e = {}
    self.add_free(const)  # the table {var: expression}

    # to cache what is already derived/inputted
    self.eqs = set()
    self.groups = []  # groups of equal pairs.

    # for why (linprog)
    self.c = []
    self.v2i = {}  # v -> index of row in A.
    self.deps = []  # equal number of columns.
    self.A = np.zeros([0, 0])  # pylint: disable=invalid-name
    self.do_why = True

  def add_free(self, v: str) -> None:
    self.v2e[v] = {v: frac(1)}

  def replace(self, v0: str, e0: dict[str, float]) -> None:
    for v, e in list(self.v2e.items()):
      self.v2e[v] = replace(e, v0, e0)

  def add_expr(self, vc: list[tuple[str, float]]) -> bool:
    """Add a new equality, represented by the list of tuples vc=[(v, c), ..]."""
    result = {}
    free = []

    for v, c in vc:
      c = frac(c)
      if v in self.v2e:
        result = plus(result, mult(self.v2e[v], c))
      else:
        free += [(v, c)]

    if free == []:  # pylint: disable=g-explicit-bool-comparison
      if is_zero(self.modulo(result)):
        return False
      result = recon(result, self.const)
      if result is None:
        return False
      v, e = result
      self.replace(v, e)

    elif len(free) == 1:
      v, m = free[0]
      self.v2e[v] = mult(result, frac(-1, m))

    else:
      dependent_v = None
      for v, m in free:
        if dependent_v is None and v != self.const:
          dependent_v = (v, m)
          continue