Giving error: name 'A' is not defined in result = compute(A,b,w,t) in controller.py file in vib3

[pythonandml]

File "C:\Users\web4sciapps-master\web4sciapps-master\doc\src\web4sa\src-web4sa\apps\flask_apps\vib3\controller.py", line 27, in index
result = compute(A, b, w, T)
NameError: name 'A' is not defined
The debugger caught an exception in your WSGI application. You can now look at the traceback which led to the error.

Please help! Thanks.