> **In this section...**   
Executing `main` to functionaly verify the `tsp` function.

<table width=100%>
 <tr width=50%>
    <td align="center"><img src="https://raw.githubusercontent.com/Xilinx/Image-Collateral/main/xilinx-logo.png" width="30%"/><h2>2020.2 Vitis™ - The Traveler Salesman Problem - Tutorial</h2>
    <a href="https://www.xilinx.com/products/design-tools/vitis.html">See Vitis™ Development Environment on xilinx.com</a>
    </td>
 </tr>
</table>

## Run the Vitis HLS C Simulation

As discussed, the testbench file is visible on the left hand side of the Vitis HLS GUI, from the *Explorer* pane: `proj->TestBench` with the file `tsp_TB.cpp`. 
Inside the tesbench we see that city coordinates are converted to distances.
City coordinates:
```cpp
  const Coord cities[] = {{40.7127837, -74.0059413 },
                          {34.0522342, -118.2436849},
                          {41.8781136, -87.6297982 },
                          {29.7604267, -95.3698028 },
                          ...
```
Calculation for distances (as previously discussed, these numbers are normalized to integers before feeding them into the `tsp` accelerator function):
```cpp
float dist = std::sqrt(
                       std::pow(cities[i].x-cities[j].x, 2)
                     + std::pow(cities[i].y-cities[j].y, 2)
                      );
```

The testbench sends 16-bit (`uint16_t`) data types transcoded from floating-point for efficient hardware processing: 
```cpp
// Normalizing distances to get the maximum precision on 16-bit integers
uint16_t maxUint = std::numeric_limits<uint16_t>::max();
for ( int i = 0; i < N*N; ++i ) {
  cout << "Distance (fp32): " << distances[i] << " Norm. (uint16): " << (uint16_t)((distances[i]/maxDist) * maxUint);
  inputDistances.write((distances[i]/maxDist) * maxUint);
}
```

Before running the simulation set the number of cities to 5 (`N=5`) in `tsp.h` to ensure a quick execution.

To run the simulation from the Vitis HLS GUI, point to the upper toolbar of the Vitis HLS GUI, locate the green 'play' icon 
![play](./images/play.png "Title")
and from its drop-down menu, select **C simulation**:

You can also alternatively use the main menu: `Project` -> `Run C Simulation`  
Once the C simulation dialog comes up, simple click OK.  
After the C simulation, the Vitis HLS GUI will look like this:

![Csim screen](./images/csim.png)

As we see on the screenshot above, the result is 75662 (scaled integer) or 51.6494. It matches the pre-computed result stored in the testbench.

## Next

* [Run the C synthesis](./csynth.md)