How to control box size?

Question

Here is my uml code:

```

@startuml

start

: Input;

: Initialize;

repeat

    : Randomly select a sample pair;

    : Forward propagation;

    : Computing gradient;

    : Back propagation;

    : Caculate <latex>J_t</latex>;

repeat while (convergence?)

: Output;

stop

@enduml

 

```

which produces:

 

 

the width of the box differs, and look not so good, how could I control it?

And the math equation seems do not work well with text.

And if I could somehow add text to the arrow from "convergence?" to loop start, it will be great.

Comments

The only way I know to have same size is using whitespace to force it.