getbase returns the whole numerical basis which builds an expression

```
B = getbase(p)
```

sdpvar variables are built-up from internal variables multiplied with numerical data. The numerical basis is extracted using

```
yalmip('clear')
x = sdpvar(1);
y = sdpvar(1);
p = 2 + 3*x + 4*y;
full(getbase(p))
ans =
2 3 4
```

This is a completely generic and fundamental structure in YALMIP. For matrices the base is vectorized

```
p = ones(2) + [1 2;3 4]*x + [5 6;7 8]*x^2
getbase(p)
ans =
1 1 5
1 2 6
1 3 7
1 4 8
```