Return fugacity coefficients, calculated from liquid and gas extremes, and Wilson k value, at given pressure, temperature and composition
pure function fugacityCoefficients_pTX input AbsolutePressure p; input Temperature T; input Real z[subsNum]; output Real fugCoefL[subsNum]; output Real fugCoefG[subsNum]; output Real kWilson[subsNum]; end fugacityCoefficients_pTX;