5.7.5 Unit, content and primitive part

The methods

ex ex::unit(const ex & x);
ex ex::content(const ex & x);
ex ex::primpart(const ex & x);
ex ex::primpart(const ex & x, const ex & c);

return the unit part, content part, and primitive polynomial of a multivariate polynomial with respect to the variable ‘x’ (the unit part being the sign of the leading coefficient, the content part being the GCD of the coefficients, and the primitive polynomial being the input polynomial divided by the unit and content parts). The second variant of primpart() expects the previously calculated content part of the polynomial in c, which enables it to work faster in the case where the content part has already been computed. The product of unit, content, and primitive part is the original polynomial.

Additionally, the method

void ex::unitcontprim(const ex & x, ex & u, ex & c, ex & p);

computes the unit, content, and primitive parts in one go, returning them in u, c, and p, respectively.