It looks like the `lambda_max`

function is attempting to access an undefined field when composed with `reshape`

. Here’s a minimal example:

```
>> n = 5; m = 10;
A = randn(m, n);
bigA = zeros(n^2, m);
for i=1:m
bigA(:,i) = vec(A(i,:)'*A(i,:));
end
cvx_begin
variable y(m)
minimize lambda_max(reshape(bigA*y, n, n))
cvx_end
Reference to non-existent field 'affine'.
Error in cvx_matrix_op (line 172)
func = p.affine;
Error in lambda_max (line 24)
y = cvx_matrix_op( params, varargin );
Error in minimize (line 8)
x = evalin( 'caller', sprintf( '%s ', varargin{:} ) );
```