# Detailed routing loops instead of straight wire...

Tool: Detailed Routing

Subcategory: Routing pattern anomaly

## Conversation

### oharboe
I've been fixing some problems in mock-array in positioning of macros and pins not being aligned and now things are working well.

However, I found this curious thing when inspecting, a detailed routing loop :-)

I don't see any reason why a horizontal wire wouldn't work here...

Any ideas or insights?

![image](https://github.com/The-OpenROAD-Project/OpenROAD/assets/2798822/381a3158-6635-452c-a270-247df28a6dae)


The above can be found if creating a `flow/settings.mk` file:

```
export DESIGN_CONFIG?=designs/asap7/mock-array/config.mk
export MOCK_ARRAY_DATAWIDTH?=8
export MOCK_ARRAY_TABLE?=8 8 4 4 5 5
export MOCK_ARRAY_SCALE?=80
```

and running `make verilog` and `make`


Various interesting things can be seen in detailed routing:

- almost all the wires are vertical/horizontal between "Element" macros. The loop above is untypical, usually it's just a slight horizontal/vertical deviation.
- there are hold cells in the middle to the right


![image](https://github.com/The-OpenROAD-Project/OpenROAD/assets/2798822/e9bca2da-5e41-4ee6-b279-e7ca375bb26a)



Hold cells have to be placed *outside* to the right of the array, hence many non-vertical vertical wires between those two elements.

![image](https://github.com/The-OpenROAD-Project/OpenROAD/assets/2798822/3a17be46-8604-498c-901f-ce375cbed5cc)


### maliberty
@osamahammad21 any thoughts on the loop?

### oharboe
A feature request filed: https://github.com/The-OpenROAD-Project/OpenROAD/issues/3634