MATLAB: Error using syms and subs

errorsubssymsymbolicSymbolic Math Toolbox

Hi all,
I'm trying to run the code that was writen in 2009 and I have this error:
Error using sym>convertChar (line 1537)
Character vectors and strings in the first argument can only specify a variable or number. To evaluate character vectors and strings representing symbolic expressions, use 'str2sym'.
Error in sym>tomupad (line 1253)
S = convertChar(x);
Error in sym (line 220)
S.s = tomupad(x);
Error in subs (line 68)
r_unique_name = subs(sym(f_unique_name),varargin{:});
The code is:
clear all
clear all;
close all;
global A1 AG AH AF rho rhod sigma alpha bet gamma eps theta deltaK deltaH Omega omeg omega0 omega1 omega3 omega4 sigma 
syms c_t x_t s_t l_t f_t a_t R_t pi_t k_t m_t gh_t z_t u_t v_t
syms r_t w_t F_t H2_t
CALIB_NCC;
SYMLOG_NCC;
FINSOL_NCC;
IMP_NCC_pi;
%SIM_NCC_pi;

Best Answer

Replacement code.
It seems likely to me that the other files would also have to be editted .
The key changes:
  1. everywhere there is a quoted expression that will be used symbolically, use str2sym() around the expression:
  2. replace simple() with simplify()
% SYMLOG_NCC
% symbolic log-linearization
% solution in x,c,R,a,f,s,l,pi,m',k',gh'
% reduced system by 1; f=c*F
eqI	= str2sym('-x_t+R*a/Ra1*(R_t+a_t)+w*F/Ra1*(w_t+F_t)-w_t+c_t');			                            % (I)
eqIIL 	= str2sym('-theta*c_t+alpha*(1-theta)*x_t-R*a/Ra1*(R_t+a_t)-w*F/Ra1*(w_t+F_t)+theta*gh_t');	                    % LHS of (II)
eqIIR	= str2sym('-theta*c_t+alpha*(1-theta)*x_t-R*a/Ra1*(R_t+a_t)-w*F/Ra1*(w_t+F_t)+r1*r_t');	% RHS of (II)
eqIIIL 	= str2sym('(1-theta)*c_t+(alpha*(1-theta)-1)*x_t-H2_t+theta*gh_t');	                                            % LHS of (III)
eqIIIR	= str2sym('(1-theta)*c_t+(alpha*(1-theta)-1)*x_t-H2_t+H21*(H2_t-x/(1-x)*x_t)');	        % RHS of (III)
eqIV    = str2sym('-a1*a_t+F_t+w_t-R_t');                                                                    % (IV)
eqVL    = str2sym('c_t+a_t');                                                                               % LHS of (V)
eqVR    = str2sym('m_t');
eqVI    = str2sym('-R_t+(pi1*pi_t+r1*r_t)/R1');			                                                    % (VI)  
eqVII   = str2sym('-F_t-1/gamma*a1*a_t-1/gamma*v_t');                                                        % (VII)
eqVIII  = str2sym('-f_t+F_t+c_t');                                                                           % (VIII)
eqIX    = str2sym('-w_t+(1-bet)*(k_t+s_t-l_t)+z_t');		                                                    % (IX)  
eqX     = str2sym('-r_t+(-bet*(s_t-l_t+k_t)+z_t)/r*(r+deltaK)');	                                            % (X)  
eqXI    = str2sym('-pi1*pi_t+u_t+m_t-gh_t-c_t-a_t');                                                         % LHS of (XI)
eqXIIL	= str2sym('y_h*((1-bet)*(k_t+s_t)+bet*l_t+z_t)+(1-deltaK)*k_h*k_t-c_h*c_t-k_h*gh*gh_t');	            % LHS of (XII)  
eqXIIR	= str2sym('k_h*gh*k_t');	                                                                            % RHS of (XII)  
eqXIII	= str2sym('H_h*((1-eps)*(k_t-s1*s_t)-eps*(x1*x_t+L1*l_t+f1*f_t))-gh*gh_t');	                        % LHS of (XIII)  
eqXIV	= str2sym('-(1+s1)*s_t+x1*x_t+(1+L1)*l_t+f1*f_t');	                                                % (XIV)  
eqXV    = str2sym('-H2_t+(1-eps)*(k_t-s1*s_t+x1*x_t+L1*l_t+f1*f_t)');                                        % (XV)  
eqI     = subs(eqI,{'Ra1','a','w','F','R'},{Ra1,a,w,F,R});
eqIIL   = subs(eqIIL,{'alpha','theta','Ra1','a','w','F','R'},{alpha,theta,Ra1,a,w,F,R});
eqIIR   = subs(eqIIR,{'alpha','theta','Ra1','a','w','F','R','r1'},{alpha,theta,Ra1,a,w,F,R,r1});
eqIIIL  = subs(eqIIIL,{'alpha','theta'},{alpha,theta});
eqIIIR  = subs(eqIIIR,{'alpha','theta','H21','x'},{alpha,theta,H21,x});
eqIV    = subs(eqIV,{'a1'},{a1});
eqVI    = subs(eqVI,{'r1','R1','pi1'},{r1,R1,pi1});
eqVII   = subs(eqVII,{'gamma','a1'},{gamma,a1});
eqIX    = subs(eqIX,{'bet'},{bet});
eqX     = subs(eqX,{'bet','deltaK','r'},{bet,deltaK,r});
eqXI    = subs(eqXI,{'pi1'},{pi1});
eqXIIL  = subs(eqXIIL,{'bet','y_h','deltaK','k_h','c_h','gh'},{bet,y_h,deltaK,k_h,c_h,gh});
eqXIIR  = subs(eqXIIR,{'k_h','gh'},{k_h,gh});
eqXIII  = subs(eqXIII,{'H_h','eps','s1','x1','L1','f1','gh'},{H_h,eps,s1,x1,L1,f1,gh});
eqXIV   = subs(eqXIV,{'s1','x1','L1','f1'},{s1,x1,L1,f1});
eqXV    = subs(eqXV,{'s1','x1','L1','f1','eps'},{s1,x1,L1,f1,eps});
w_t     = simplify(solve(eqIX,'w_t'));     % 
F_t     = simplify(solve(eqVII,'F_t'));
H2_t    = simplify(solve(eqXV,'H2_t'));
r_t     = simplify(solve(eqX,'r_t'));
eqVIII  = subs(eqVIII,{'F_t'},{F_t});
f_t     = simplify(solve(eqVIII,'f_t'));
H2_t    = subs(H2_t,{'f_t'},{f_t});
eqXIII  = subs(eqXIII,{'f_t'},{f_t});
gh_t    = simplify(solve(eqXIII,'gh_t'));
eqVI    = subs(eqVI,{'r_t'},{r_t});
R_t     = simplify(solve(eqVI,'R_t'));
eqVI    = subs(eqVI,{'r_t'},{r_t});
eqXI    = subs(eqXI,{'gh_t'},{gh_t});
pi_t    = simplify(solve(eqXI,'pi_t'));
R_t     = subs(R_t,{'pi_t'},{pi_t});
eqIV    = subs(eqIV,{'F_t','w_t','R_t'},{F_t,w_t,R_t});
a_t     = simplify(solve(eqIV,'a_t'));
%eqV     = subs(eqV,{'a_t'},{a_t});
% c_t     = simplify(solve(eqV,'c_t'));
% a_t     = subs(a_t,{'c_t'},{c_t});
%f_t     = subs(f_t,{'a_t','c_t'},{a_t,c_t});
f_t     = subs(f_t,{'a_t'},{a_t});
eqXIV   = subs(eqXIV,{'f_t'},{f_t});
s_t     = simplify(solve(eqXIV,'s_t'));
a_t     = subs(a_t,{'s_t'},{s_t});
%c_t     = subs(c_t,{'s_t'},{s_t});
R_t     = subs(R_t,{'s_t','a_t'},{s_t,a_t});
w_t     = subs(w_t,{'s_t'},{s_t});
F_t     = subs(F_t,{'a_t'},{a_t});
r_t     = subs(r_t,{'s_t'},{s_t});
eqI	    = subs(eqI,{'w_t','F_t','R_t','a_t'},{w_t,F_t,R_t,a_t});
x_t     = simplify(solve(eqI,'x_t'));
s_t     = subs(s_t,{'x_t'},{x_t});
%c_t     = subs(c_t,{'x_t'},{x_t});
a_t     = subs(a_t,{'x_t'},{x_t});
f_t     = subs(f_t,{'x_t','s_t'},{x_t,s_t});
w_t     = subs(w_t,{'x_t'},{x_t});
F_t     = subs(F_t,{'x_t'},{x_t});
H2_t    = subs(H2_t,{'s_t','a_t','x_t'},{s_t,a_t,x_t});
gh_t    = subs(gh_t,{'s_t','f_t','x_t','a_t'},{s_t,f_t,x_t,a_t});
R_t     = subs(R_t,{'x_t'},{x_t});
r_t     = subs(r_t,{'x_t'},{x_t});
pi_t    = subs(pi_t,{'s_t','a_t','x_t'},{s_t,a_t,x_t});
% solution in k,m,m1,l,z,u,v
eqIIL   = subs(eqIIL,{'x_t','R_t','a_t','w_t','F_t','gh_t'},{x_t,R_t,a_t,w_t,F_t,gh_t});
eqIIR   = subs(eqIIR,{'x_t','R_t','a_t','w_t','F_t','r_t'},{x_t,R_t,a_t,w_t,F_t,r_t});
eqIIIL  = subs(eqIIIL,{'x_t','H2_t','gh_t'},{x_t,H2_t,gh_t});
eqIIIR  = subs(eqIIIR,{'x_t','H2_t'},{x_t,H2_t});
eqXIIL  = subs(eqXIIL,{'gh_t','s_t','x_t','f_t'},{gh_t,s_t,x_t,f_t});
eqVL    = subs(eqVL,{'a_t'},{a_t});
eqVR    = subs(eqVR,{'m_t'},{m_t});
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