some question

[dongjinyang15]

Hi, I'm trying to get Cassie's dynamics Model. I followed the steps, but I get the following error message ¿What could I be doing wrong?
错误使用 eval_math (第 46 行)
The evaluation of Mathematica expression failed.

出错 SymExpression (第 91 行)
eval_math([obj.s '=' obj.f ';']);

出错 eval_math_fun (第 53 行)
ret = SymExpression(fstr,varargin{:});

出错 RobotLinks/configureDynamics (第 44 行)
De{i} = eval_math_fun('InertiaMatrixByLink',[links(i),{obj.numState}]);

出错 model_gen (第 36 行)
cassie.configureDynamics('DelayCoriolisSet',false);

[1190201119]

I have met the same question, and I solved it. You should change your Mathematica version<13.1

Every time when I run "frost_addpath" the first time, it will fail and say something about symbol "BlockDiagonalMatrix", both defined in frost and system builtin, (I'm not sure, because I don't familiar with Mathematica)see https://reference.wolfram.com/language/ref/BlockDiagonalMatrix.html. So I used version 13.0.1, the problem disappeard.