@Carl Love 

Worked like a charm. thanks alot!

this is the same code but you can copy it :)

destination3 := Join([ParentDirectory(ParentDirectory(ParentDirectory(currentdir()))), "/Rayleigh_et_Timoshenko/Timoshenko/Matlab Samy/"], ""); destination3 := sprintf("cd ('%s%s%s')", "", destination3, ""); openlink(); evalM(destination3); Matlab:-evalM("which -all convergence4"); evalM(sprintf("result=convergence4(%e,%e,%e,%e,%e)", gamm, s, `ρ_moy`, E_effective_xx, l)); matrice := getvar("result"); closelink();

You are my savior! thx a lot

You are my savior! thx a lot