Early in my program I define a 4x4 matrix:
Later I wish to allow the user to modify a matrix element:
''A''<>sur<>''x''[1,1]=Input[''New a33 x value'']];
I am getting this error when I try to use the new A1x matrix:
SetDelayed::write: Tag StringJoin in A<>1<>x is Protected.
Please explain this error, and if there is a way to avoid it. Thanks.