Example 5 – Comparison of PMFA and alternative methods. We use the model described in Figure 1 assuming that v2, v3, v4 and v5 have been measured (depicted in grey). The flux estimation was performed with four methods: PMFA, Traditional MFA (TMFA), MFA as a constraint weighted least-squares problem (LS-MFA) and the flux spectrum approach (FS-MFA). The marginal distribution computed with PMFA are depicted in blue, the point-wise estimation of TMFA and LS-MFA are depicted in light and dark grey respectively, and the interval estimation of FS-MFA in green. In (B) the maximum possibility flux estimation and the flux intervals for conditional possibilities of 0.8 (box), 0.5 (thick line) and 0.1 (narrow line) are compared with the estimations given by TMFA, LS-MFA and FS-MFA.