# This function solves for `x' in the set of simultaneous linear equations
#
#	A*x = b
#
# It's argument `A' may be either the coefficient matrix itself, or a
# previously factored matrix in the form of the output of the `factor'
# or `chol' functions.
#
# If the optional table `options' contains a member named "pos", then
# `A' is taken to be positive definite and Cholesky factorization is
# performed instead of the more expensive general method.

solve = function (A; b; options)
{
  if (class(A) != "table")
  {
    if (options != NULL && members (options) == "pos")
    {
      A = chol (A);
    else
      A = factor (A);
    }
  }

  return backsub (A; b);
};