## Backwd Flat

Subtype of Interp MethodThe reference quantity is interpolated according to the QuantLib BackwardFlat method.

The value at a node is extended flatly back to the previous node.

Formally, given any two successive nodes

**and**

*(x₁,v₁)***then the value**

*(x₂,v₂)***corresponding to some**

*v***lying strictly between**

*x***and**

*x₁***is given by**

*x₂*

*v = x2*