function [F_BUS, T_BUS, BR_R, BR_X, BR_B, RATE_A, RATE_B, ...    RATE_C, TAP, SHIFT, BR_STATUS, PF, QF, PT, QT, MU_SF, MU_ST, ...    ANGMIN, ANGMAX, MU_ANGMIN, MU_ANGMAX] = idx_brch%IDX_BRCH   Defines constants for named column indices to branch matrix.%   [F_BUS, T_BUS, BR_R, BR_X, BR_B, RATE_A, RATE_B, RATE_C, ...%   TAP, SHIFT, BR_STATUS, PF, QF, PT, QT, MU_SF, MU_ST, ...%   ANGMIN, ANGMAX, MU_ANGMIN, MU_ANGMAX] = idx_brch%%   Some examples of usage, after defining the constants using the line above,%   are:%%    branch(4, BR_STATUS) = 0;              % take branch 4 out of service%    Ploss = branch(:, PF) + branch(:, PT); % compute real power loss vector% %   The index, name and meaning of each column of the branch matrix is given%   below:%%   columns 1-11 must be included in input matrix (in case file)%    1  F_BUS       f, from bus number%    2  T_BUS       t, to bus number%    3  BR_R        r, resistance (p.u.)%    4  BR_X        x, reactance (p.u.)%    5  BR_B        b, total line charging susceptance (p.u.)%    6  RATE_A      rateA, MVA rating A (long term rating)%    7  RATE_B      rateB, MVA rating B (short term rating)%    8  RATE_C      rateC, MVA rating C (emergency rating)%    9  TAP         ratio, transformer off nominal turns ratio%    10 SHIFT       angle, transformer phase shift angle (degrees)%    11 BR_STATUS   initial branch status, 1 - in service, 0 - out of service%    12 ANGMIN      minimum angle difference, angle(Vf) - angle(Vt) (degrees)%    13 ANGMAX      maximum angle difference, angle(Vf) - angle(Vt) (degrees)%%   columns 14-17 are added to matrix after power flow or OPF solution%   they are typically not present in the input matrix%    14 PF          real power injected at "from" bus end (MW)%    15 QF          reactive power injected at "from" bus end (MVAr)%    16 PT          real power injected at "to" bus end (MW)%    17 QT          reactive power injected at "to" bus end (MVAr)%%   columns 18-19 are added to matrix after OPF solution%   they are typically not present in the input matrix%                   (assume OPF objective function has units, u)%    18 MU_SF       Kuhn-Tucker multiplier on MVA limit at "from" bus (u/MVA)%    19 MU_ST       Kuhn-Tucker multiplier on MVA limit at "to" bus (u/MVA)%%   columns 20-21 are added to matrix after SCOPF solution%   they are typically not present in the input matrix%                   (assume OPF objective function has units, u)%    20 MU_ANGMIN   Kuhn-Tucker multiplier lower angle difference limit (u/degree)%    21 MU_ANGMAX   Kuhn-Tucker multiplier upper angle difference limit (u/degree)%   MATPOWER%   $Id: idx_brch.m,v 1.7 2007/05/31 18:45:55 ray Exp $%   by Ray Zimmerman, PSERC Cornell%   Copyright (c) 1996-2005 by Power System Engineering Research Center (PSERC)%   See http://www.pserc.cornell.edu/matpower/ for more info.%% define the indicesF_BUS       = 1;    %% f, from bus numberT_BUS       = 2;    %% t, to bus numberBR_R        = 3;    %% r, resistance (p.u.)BR_X        = 4;    %% x, reactance (p.u.)BR_B        = 5;    %% b, total line charging susceptance (p.u.)RATE_A      = 6;    %% rateA, MVA rating A (long term rating)RATE_B      = 7;    %% rateB, MVA rating B (short term rating)RATE_C      = 8;    %% rateC, MVA rating C (emergency rating)TAP         = 9;    %% ratio, transformer off nominal turns ratioSHIFT       = 10;   %% angle, transformer phase shift angle (degrees)BR_STATUS   = 11;   %% initial branch status, 1 - in service, 0 - out of serviceANGMIN      = 12;   %% minimum angle difference, angle(Vf) - angle(Vt) (degrees)ANGMAX      = 13;   %% maximum angle difference, angle(Vf) - angle(Vt) (degrees)%% included in power flow solution, not necessarily in inputPF          = 14;   %% real power injected at "from" bus end (MW)       (not in PTI format)QF          = 15;   %% reactive power injected at "from" bus end (MVAr) (not in PTI format)PT          = 16;   %% real power injected at "to" bus end (MW)         (not in PTI format)QT          = 17;   %% reactive power injected at "to" bus end (MVAr)   (not in PTI format)%% included in opf solution, not necessarily in input%% assume objective function has units, uMU_SF       = 18;   %% Kuhn-Tucker multiplier on MVA limit at "from" bus (u/MVA)MU_ST       = 19;   %% Kuhn-Tucker multiplier on MVA limit at "to" bus (u/MVA)MU_ANGMIN   = 20;   %% Kuhn-Tucker multiplier lower angle difference limit (u/degree)MU_ANGMAX   = 21;   %% Kuhn-Tucker multiplier upper angle difference limit (u/degree)return;