What is the role of & in this piece of code?
 

Hi!
I am very new to start understanding the coding of openfoam.


I am trying to understand dbns code in foam-extend. But I am having bit of doubt in a specific part of the following code given below.


deltaRLeft & gradrho[own] or
deltaRRight & gradU[nei]
I thing & used here is a reference operator, but if any one can explain it in more detail, it will helpful for me.


Flux::evaluateFlux (

rhoFlux_[faceI],

rhoUFlux_[faceI],

rhoEFlux_[faceI],

rho_[own] + rhoLimiter[own]*(deltaRLeft & gradrho[own]),

rho_[nei] + rhoLimiter[nei]*(deltaRRight & gradrho[nei]),

U_[own] + cmptMultiply(ULimiter[own], (deltaRLeft & gradU[own])),

U_[nei] + cmptMultiply(ULimiter[nei], (deltaRRight & gradU[nei])),

T_[own] + TLimiter[own]*(deltaRLeft & gradT[own]),

T_[nei] + TLimiter[nei]*(deltaRRight & gradT[nei]),

R[own],

R[nei],

Cv[own],

Cv[nei],

Cp[own],

Cp[nei],

Sf[faceI],

magSf[faceI] );

What is the & exactly doing here, if it can be explained in detail. The part of the code is from dbns/numericFlux/numericFlux.C

I am sorry. I could understand it.