MODCOST Modifies generator costs by shifting or scaling (F or X).
NEWGENCOST = MODCOST(GENCOST, ALPHA)
NEWGENCOST = MODCOST(GENCOST, ALPHA, MODTYPE)
For each generator cost F(X) (for real or reactive power) in
GENCOST, this function modifies the cost by scaling or shifting
the function by ALPHA, depending on the value of MODTYPE, and
and returns the modified GENCOST. Rows of GENCOST can be a mix
of polynomial or piecewise linear costs. ALPHA can be a scalar,
applied to each row of GENCOST, or an NG x 1 vector, where each
element is applied to the corresponding row of GENCOST.
MODTYPE takes one of the 4 possible values (let F_alpha(X) denote the
the modified function):
'SCALE_F' (default) : F_alpha(X) == F(X) * ALPHA
'SCALE_X' : F_alpha(X * ALPHA) == F(X)
'SHIFT_F' : F_alpha(X) == F(X) + ALPHA
'SHIFT_X' : F_alpha(X + ALPHA) == F(X)0001 function gencost = modcost(gencost, alpha, modtype) 0002 %MODCOST Modifies generator costs by shifting or scaling (F or X). 0003 % NEWGENCOST = MODCOST(GENCOST, ALPHA) 0004 % NEWGENCOST = MODCOST(GENCOST, ALPHA, MODTYPE) 0005 % 0006 % For each generator cost F(X) (for real or reactive power) in 0007 % GENCOST, this function modifies the cost by scaling or shifting 0008 % the function by ALPHA, depending on the value of MODTYPE, and 0009 % and returns the modified GENCOST. Rows of GENCOST can be a mix 0010 % of polynomial or piecewise linear costs. ALPHA can be a scalar, 0011 % applied to each row of GENCOST, or an NG x 1 vector, where each 0012 % element is applied to the corresponding row of GENCOST. 0013 % 0014 % MODTYPE takes one of the 4 possible values (let F_alpha(X) denote the 0015 % the modified function): 0016 % 'SCALE_F' (default) : F_alpha(X) == F(X) * ALPHA 0017 % 'SCALE_X' : F_alpha(X * ALPHA) == F(X) 0018 % 'SHIFT_F' : F_alpha(X) == F(X) + ALPHA 0019 % 'SHIFT_X' : F_alpha(X + ALPHA) == F(X) 0020 0021 % MATPOWER 0022 % $Id: modcost.m 2189 2013-07-30 16:23:31Z ray $ 0023 % by Ray Zimmerman, PSERC Cornell 0024 % Copyright (c) 2010 by Power System Engineering Research Center (PSERC) 0025 % 0026 % This file is part of MATPOWER. 0027 % See http://www.pserc.cornell.edu/matpower/ for more info. 0028 % 0029 % MATPOWER is free software: you can redistribute it and/or modify 0030 % it under the terms of the GNU General Public License as published 0031 % by the Free Software Foundation, either version 3 of the License, 0032 % or (at your option) any later version. 0033 % 0034 % MATPOWER is distributed in the hope that it will be useful, 0035 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0036 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0037 % GNU General Public License for more details. 0038 % 0039 % You should have received a copy of the GNU General Public License 0040 % along with MATPOWER. If not, see <http://www.gnu.org/licenses/>. 0041 % 0042 % Additional permission under GNU GPL version 3 section 7 0043 % 0044 % If you modify MATPOWER, or any covered work, to interface with 0045 % other modules (such as MATLAB code and MEX-files) available in a 0046 % MATLAB(R) or comparable environment containing parts covered 0047 % under other licensing terms, the licensors of MATPOWER grant 0048 % you additional permission to convey the resulting work. 0049 0050 %% define named indices into data matrices 0051 [PW_LINEAR, POLYNOMIAL, MODEL, STARTUP, SHUTDOWN, NCOST, COST] = idx_cost; 0052 0053 if nargin < 3 0054 modtype = 'SCALE_F'; 0055 end 0056 0057 [ng, m] = size(gencost); 0058 0059 if ng ~= 0 0060 if length(alpha) ~= ng 0061 if length(alpha) == 1 && ng > 1 %% scalar, make it a col vector 0062 alpha = alpha * ones(ng, 1); 0063 else 0064 error('modcost: ALPHA must be a scalar or col vector with NG rows'); 0065 end 0066 elseif size(alpha, 2) ~= 1 0067 alpha = alpha'; %% convert row vector to col vector 0068 end 0069 0070 ipwl = find(gencost(:, MODEL) == PW_LINEAR); 0071 ipol = find(gencost(:, MODEL) == POLYNOMIAL); 0072 c = gencost(ipol, COST:m); 0073 0074 switch modtype 0075 case 'SCALE_F', 0076 gencost(ipol, COST:m) = diag(alpha(ipol)) * c; 0077 gencost(ipwl, COST+1:2:m) = diag(alpha(ipwl)) * gencost(ipwl, COST+1:2:m); 0078 case 'SCALE_X', 0079 for k = 1:length(ipol) 0080 n = gencost(ipol(k), NCOST); 0081 for i = 1:n 0082 gencost(ipol(k), COST+i-1) = c(k, i) / alpha(ipol(k))^(n-i); 0083 end 0084 end 0085 gencost(ipwl, COST:2:m-1) = diag(alpha(ipwl)) * gencost(ipwl, COST:2:m-1); 0086 case 'SHIFT_F', 0087 for k = 1:length(ipol) 0088 n = gencost(ipol(k), NCOST); 0089 gencost(ipol(k), COST+n-1) = alpha(ipol(k)) + c(k, n); 0090 end 0091 gencost(ipwl, COST+1:2:m) = ... 0092 diag(alpha(ipwl)) * ones(length(ipwl), (m+1-COST)/2) + ... 0093 gencost(ipwl, COST+1:2:m); 0094 case 'SHIFT_X', 0095 for k = 1:length(ipol) 0096 n = gencost(ipol(k), NCOST); 0097 gencost(ipol(k), COST:COST+n-1) = polyshift(c(k, 1:n)', alpha(ipol(k)))'; 0098 end 0099 gencost(ipwl, COST:2:m-1) = ... 0100 diag(alpha(ipwl)) * ones(length(ipwl), (m+1-COST)/2) + ... 0101 gencost(ipwl, COST:2:m-1); 0102 otherwise 0103 error('modcost: ''%s'' is not a valid modtype\n', modtype); 0104 end 0105 end 0106 0107 0108 %%----- POLYSHIFT ----- 0109 function d = polyshift(c, a) 0110 %POLYSHIFT Returns the coefficients of a horizontally shifted polynomial. 0111 % 0112 % D = POLYSHIFT(C, A) shifts to the right by A, the polynomial whose 0113 % coefficients are given in the column vector C. 0114 % 0115 % Example: For any polynomial with n coefficients in c, and any values 0116 % for x and shift a, the f - f0 should be zero. 0117 % x = rand; 0118 % a = rand; 0119 % c = rand(n, 1); 0120 % f0 = polyval(c, x) 0121 % f = polyval(polyshift(c, a), x+a) 0122 0123 n = length(c); 0124 d = zeros(size(c)); 0125 A = (-a * ones(n, 1)) .^ ((0:n-1)'); 0126 b = ones(n, 1); 0127 for k = 1:n 0128 d(n-k+1) = b' * ( c(n-k+1:-1:1) .* A(1:n-k+1) ); 0129 b = cumsum(b(1:n-k)); 0130 end