Skip to main content

Unconstrained

Defined in: lib/provable/types/unconstrained.ts:39

Container which holds an unconstrained value. This can be used to pass values between the out-of-circuit blocks in provable code.

Invariants:

  • An Unconstrained's value can only be accessed in auxiliary contexts.
  • An Unconstrained can be empty when compiling, but never empty when running as the prover. (there is no way to create an empty Unconstrained in the prover)

Example​

let x = Unconstrained.from(0n);

class MyContract extends SmartContract {
  `@method` myMethod(x: Unconstrained<bigint>) {

    Provable.witness(Field, () => {
      // we can access and modify `x` here
      let newValue = x.get() + otherField.toBigInt();
      x.set(newValue);

      // ...
    });

    // throws an error!
    x.get();
  }

Type Parameters​

T​

T

Properties​

provable​

static provable: UnconstrainedProvable<any> & {
  empty: () => Unconstrained<any>;
  toInput: (x: Unconstrained<any>) => {
     fields?: Field[];
     packed?: [Field, number][];
  };
};

Defined in: lib/provable/types/unconstrained.ts:109

Type declaration​

empty()​
empty: () => Unconstrained<any>;
Returns​

Unconstrained<any>

toInput()​
toInput: (x: Unconstrained<any>) => {
  fields?: Field[];
  packed?: [Field, number][];
};
Parameters​
x​

Unconstrained<any>

Returns​
{
  fields?: Field[];
  packed?: [Field, number][];
}
fields?​
optional fields: Field[];
packed?​
optional packed: [Field, number][];

Methods​

get()​

get(): T;

Defined in: lib/provable/types/unconstrained.ts:51

Read an unconstrained value.

Note: Can only be called outside provable code.

Returns​

T

set()​

set(value: T): void;

Defined in: lib/provable/types/unconstrained.ts:65

Modify the unconstrained value.

Parameters​

value​

T

Returns​

void

setTo()​

setTo(value: Unconstrained<T>): void;

Defined in: lib/provable/types/unconstrained.ts:72

Set the unconstrained value to the same as another Unconstrained.

Parameters​

value​

Unconstrained<T>

Returns​

void

updateAsProver()​

updateAsProver(compute: (value: T) => T): void;

Defined in: lib/provable/types/unconstrained.ts:102

Update an Unconstrained by a witness computation.

Parameters​

compute​

(value: T) => T

Returns​

void

from()​

static from<T>(value: T | Unconstrained<T>): Unconstrained<T>;

Defined in: lib/provable/types/unconstrained.ts:87

Create an Unconstrained with the given value.

Note: If T contains provable types, Unconstrained.from is an anti-pattern, because it stores witnesses in a space that's intended to be used outside the proof. Something like the following should be used instead:

let xWrapped = Unconstrained.witness(() => Provable.toConstant(type, x));

Type Parameters​

T​

T

Parameters​

value​

T | Unconstrained<T>

Returns​

Unconstrained<T>

withEmpty()​

static withEmpty<T>(empty: T): Provable<Unconstrained<T>, T> & {
  empty: () => Unconstrained<T>;
  toInput: (x: Unconstrained<T>) => {
     fields?: Field[];
     packed?: [Field, number][];
  };
};

Defined in: lib/provable/types/unconstrained.ts:129

Type Parameters​

T​

T

Parameters​

empty​

T

Returns​

Provable<Unconstrained<T>, T> & { empty: () => Unconstrained<T>; toInput: (x: Unconstrained<T>) => { fields?: Field[]; packed?: [Field, number][]; }; }

witness()​

static witness<T>(compute: () => T): Unconstrained<T>;

Defined in: lib/provable/types/unconstrained.ts:95

Create an Unconstrained from a witness computation.

Type Parameters​

T​

T

Parameters​

compute​

() => T

Returns​

Unconstrained<T>