rdzman
commented
5 years ago Thanks for this suggestion.
Unfortunately, it seems the improved performance is not so consistent. In particular, for me it looks like the improvement only applies to very small systems and the change actually slows things down for larger systems, but only on MATLAB, not on Octave.
Running time_makeYbus.m, which also requires makeYbus_new.m, results in output like the following on my machine.
Note: You'll need to remove the .txt extension from each after downloading the two files linked above.
On MATLAB:
>> time_makeYbus
case9 : 10000 reps : speedup = 24.6%
case39 : 2329 reps : speedup = 7.0%
case57 : 1603 reps : speedup = 6.3%
case118 : 789 reps : speedup = 1.2%
case300 : 327 reps : speedup = -1.5%
case2383wp : 66 reps : speedup = -7.9%
case6515rte : 42 reps : speedup = -17.7%
case13659pegase : 35 reps : speedup = -10.6%
case_ACTIVSg70k : 30 reps : speedup = -13.6%On Octave:
octave:1> time_makeYbus
case9 : 10000 reps : speedup = 4.6%
case39 : 2329 reps : speedup = 5.9%
case57 : 1603 reps : speedup = 7.1%
case118 : 789 reps : speedup = 11.2%
case300 : 327 reps : speedup = 16.2%
case2383wp : 66 reps : speedup = 22.5%
case6515rte : 42 reps : speedup = 9.6%
case13659pegase : 35 reps : speedup = 11.0%
case_ACTIVSg70k : 30 reps : speedup = 12.4%Just out of curiosity, could you post the output of a typical run on your machine?
AsprinChina
In makeYbus.m, we use the multiplication of the connection matrices and branch admittance matrices to get the node admittance matrices, like this:
mpc = case39(); for i=1:100000 makeYbus(mpc); end for i=1:100000 makeYbus_modified(mpc); endThe time consumed are shown in this figure.
The makeYbus_modified.m is `function [Ybus, Yf, Yt] = makeYbus(baseMVA, bus, branch) %MAKEYBUS Builds the bus admittance matrix and branch admittance matrices. % [YBUS, YF, YT] = MAKEYBUS(MPC) % [YBUS, YF, YT] = MAKEYBUS(BASEMVA, BUS, BRANCH) %
% Returns the full bus admittance matrix (i.e. for all buses) and the % matrices YF and YT which, when multiplied by a complex voltage vector, % yield the vector currents injected into each line from the "from" and % "to" buses respectively of each line. Does appropriate conversions to p.u. % Inputs can be a MATPOWER case struct or individual BASEMVA, BUS and % BRANCH values. Bus numbers must be consecutive beginning at 1 % (i.e. internal ordering). % % See also MAKEJAC, MAKESBUS, EXT2INT.
% MATPOWER % Copyright (c) 1996-2016, Power Systems Engineering Research Center (PSERC) % by Ray Zimmerman, PSERC Cornell % % This file is part of MATPOWER. % Covered by the 3-clause BSD License (see LICENSE file for details). % See http://www.pserc.cornell.edu/matpower/ for more info.
%% extract from MPC if necessary if nargin < 3 mpc = baseMVA; baseMVA = mpc.baseMVA; bus = mpc.bus; branch = mpc.branch; end
%% constants nb = size(bus, 1); %% number of buses nl = size(branch, 1); %% number of lines
%% define named indices into bus, branch matrices [PQ, PV, REF, NONE, BUS_I, BUS_TYPE, PD, QD, GS, BS, BUS_AREA, VM, ... VA, BASE_KV, ZONE, VMAX, VMIN, LAM_P, LAM_Q, MU_VMAX, MU_VMIN] = idx_bus; [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;
%% check that bus numbers are equal to indices to bus (one set of bus numbers) if any(bus(:, BUS_I) ~= (1:nb)') error('makeYbus: buses must be numbered consecutively in bus matrix; use ext2int() to convert to internal ordering') end
%% for each branch, compute the elements of the branch admittance matrix where %% %% | If | | Yff Yft | | Vf | %% | | = | | | | %% | It | | Ytf Ytt | | Vt | %% stat = branch(:, BR_STATUS); %% ones at in-service branches Ys = stat ./ (branch(:, BR_R) + 1j branch(:, BR_X)); %% series admittance Bc = stat . branch(:, BR_B); %% line charging susceptance tap = ones(nl, 1); %% default tap ratio = 1 i = find(branch(:, TAP)); %% indices of non-zero tap ratios tap(i) = branch(i, TAP); %% assign non-zero tap ratios tap = tap . exp(1jpi/180 branch(:, SHIFT)); %% add phase shifters Ytt = Ys + 1jBc/2;
Yff = Ytt ./ (tap . conj(tap)); %
Yft = - Ys ./ conj(tap); Ytf = - Ys ./ tap;
%% compute shunt admittance %% if Psh is the real power consumed by the shunt at V = 1.0 p.u. %% and Qsh is the reactive power injected by the shunt at V = 1.0 p.u. %% then Psh - j Qsh = V conj(Ysh V) = conj(Ysh) = Gs - j Bs, %% i.e. Ysh = Psh + j Qsh, so ... Ysh = (bus(:, GS) + 1j * bus(:, BS)) / baseMVA; %% vector of shunt admittances
%% build connection matrices f = branch(:, F_BUS); %% list of "from" buses t = branch(:, T_BUS); %% list of "to" buses
%% build Ybus i = [1:nl; 1:nl]';
Yf = sparse(i, [f; t], [Yff; Yft], nl, nb); Yt = sparse(i, [f; t], [Ytf; Ytt], nl, nb); Ybus = sparse([f,f,t,t], [f,t,f,t], [Yff,Yft,Ytf,Ytt], nb, nb) + ... %% branch admittances sparse(1:nb, 1:nb, Ysh, nb, nb); %% shunt admittance ` Hope you could adopt this suggestion, and thanks for providing such a powerful instrument!