Hi,
I'm not sure how to fix this error. I tried using str2sym() function to create the variables instead of syms but I get the same error. I'm following the 2016 SOSTOOLS manual but using MATLAB 2019b with the latest SOSTOOLS github files.
>> syms x1 x2;
>> V = findlyap(f,[x1; x2],2)
Error using sym>convertChar (line 1548)
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 1255)
S = convertChar(x);
Error in sym (line 222)
S.s = tomupad(x);
Error in mysympower (line 58)
ZTemp = sym(ZTemp);
Error in findlyap (line 96)
expr1 = expr1 - epsmat(i,:) * mysympower(vars(i),[2:2:degree]');
Thanks,
Matt