# Max() function problem

When i use max() function inside the cvx to get max values for one dimension of a matrix inside cvx i get false results for max values.If i do it after cvx_end ,it gives me correct results.I cant do it afterwards because i want the max values for a constraint inside cvx. The matrix has some of the variables as items.Any help?

You haven’t shown us reproducible code, nor explained what these “false results” consist of.

Have you been following CVX’s rules?

help cvx/max
Disciplined convex/geometric programming information:
max is convex, log-log-convex, and nondecreasing in its first
two arguments. Thus when used in disciplined convex programs,
both arguments must be convex (or affine). In disciplined
geometric programs, both arguments must be log-convex/affine.

Here is an example of max being used in CVX.

``````cvx_begin
variable x(4)
minimize(max(x))
1 <= x <= 2
sum(x) == 5
x(1)  + .5 <= x(2) <= x(3) +.2
cvx_end
``````

With the result:

``````disp(x)
1.000000001845220
1.500000003654262
1.394764374540845
1.105235619953878
``````

`max` can also be used in constraints, when in compliance with DCP rules.