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.