# Vector Variables

Vector fields refer to a coordinate vector **$(\mathbf{u}, \mathbf{v})$**.

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## Steps to Display Vectors

1. **Primary menu** → [file name] → `uo`, then **Secondary menu** → `u` → `interp`.
2. **Primary menu** → [file name] → `vo`, then **Secondary menu** → `v` → `interp`.

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## Behavior with a Variable **$p$** Assigned

If **$p$** is **not assigned**:
- The **colorbar** will reflect the **vector norm**: **$p = \sqrt{u^2 + v^2}$**.
- The **arrow size** will be **fixed**.
- The colorbar range and isolines are controlled by **$u$**.

If another variable is assigned to **$p$**:
- The **colorbar** will reflect the value of **$p$.
- The **arrow size** will reflect the amplitude of the vector, i.e.:
  **$V = \sqrt{u^2 + v^2}$**.
- The colorbar range and isolines are thus controlled by **$p$**.

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## Visual Examples

### Without **$p$** Defined: Vector Amplitude
![Vector Amplitude](../../_static/quiver_uv.jpg)

### With **$p$** Defined: Value of **$p$**
![Value of p](../../_static/quiver_p.jpg)

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## Clearing the Assignment of **$p$** (or **$u$**, **$v$**)
To clear the assignment of a variable:

1. **Primary menu** → [file name] → [assigned variable], then **Secondary menu** → `Clear`.