opf_branch_ang_fcn

opf_branch_ang_fcn(x, Aang, lang, uang)

opf_branch_ang_fcn() - Evaluates branch angle difference constraints and gradients.

[VADIF, DVADIF] = OPF_BRANCH_ANG_FCN(X, AANG, LANG, UANG);

Computes the lower and upper constraints on branch angle differences
for voltages in cartesian coordinates. Computes constraint vectors and
their gradients. The constraints are of the form:
    Aang * Va >= lang
    Aang * Va <= uang
where Va is the voltage angle, a non-linear function of the Vr and Vi.

Inputs:
  X : optimization vector
  AANG : constraint matrix, see MAKEAANG
  LANG : lower bound vector, see MAKEAANG
  UANG : upper bound vector, see MAKEAANG

Outputs:
  VADIF  : constraint vector [ lang - Aang * Va; Aang * Va - uang ]
  DVADIF : (optional) constraint gradients

Examples:
    VaDif = opf_branch_ang_fcn(x, Aang, lang, uang);
    [VaDif, dVaDif] = opf_branch_ang_fcn(x, Aang, lang, uang);