# Trait sp_weights::WeightToFeePolynomial

source · ```
pub trait WeightToFeePolynomial {
type Balance: BaseArithmetic + From<u32> + Copy + Unsigned;
// Required method
fn polynomial() -> WeightToFeeCoefficients<Self::Balance>;
}
```

## Expand description

A trait that describes the weight to fee calculation as polynomial.

An implementor should only implement the `polynomial`

function.

## Required Associated Types§

## Required Methods§

source#### fn polynomial() -> WeightToFeeCoefficients<Self::Balance>

#### fn polynomial() -> WeightToFeeCoefficients<Self::Balance>

Returns a polynomial that describes the weight to fee conversion.

This is the only function that should be manually implemented. Please note
that all calculation is done in the probably unsigned `Balance`

type. This means
that the order of coefficients is important as putting the negative coefficients
first will most likely saturate the result to zero mid evaluation.