getvariables returns the internal index associated with an sdpvar variable

### Syntax

k = getvariables(x)


### Examples

sdpvar variables are built-up from internal variable indicies (i.e., the only internal name and reference is an integer).

yalmip('clear')
x = sdpvar(1);
getvariables(x)

ans =
1

y = sdpvar(2,3);
getvariables(y)
ans =
2 3 4 5 6 7


Also nonlinear terms have internal indicies (and assosciated structures to explain how the term relates to other linear variables)

z = x^2;
getvariables(z)
ans =
8


Expressions are built up from variables

z = x + 3*x^2;
getvariables(z)
ans =
1 8


### Commnents

In most situations you typically use depends which returns the index to the involved linear variables.