void set_r(const double r) {
        vector_fp moleFracs(2);
        moleFracs[0] = r;
        moleFracs[1] = 1-r;
	test_phase->setMoleFractions(&moleFracs[0]);

    }
void MaskellSolidSolnPhase::calcDensity()
{
    const vector_fp& vbar = getStandardVolumes();

    vector_fp moleFracs(m_kk);
    Phase::getMoleFractions(&moleFracs[0]);
    doublereal vtotal = 0.0;
    for (size_t i = 0; i < m_kk; i++) {
        vtotal += vbar[i] * moleFracs[i];
    }
    Phase::setDensity(meanMolecularWeight() / vtotal);
}