FixedI128

Composite 187 v411

substrate_fixed::FixedI128

About This Type

Signed binary fixed-point integer with `.bits` codec (substrate-fixed).

Subtensor uses substrate-fixed FixedI128<Frac> aliases (commonly I64F64, sometimes I96F32) for signed quantities like EMAs, weights, and consensus calculations. The chain typeName drops the Frac type parameter; resolve it from the use-site alias.

Encoding: Signed substrate-fixed types encode in two's complement. BigInt("0x...") in JS does NOT sign-extend — for a negative value it returns a huge positive integer. Mask to the inner bit width and adjust manually (e.g. for i128: `v >= 2n**127n ? v - 2n**128n : v`).

For I64F64 (Frac=64): real = bits / 2^64. For I96F32 (Frac=32): real = bits / 2^32.

Common Uses

  • • EMA tracking (SubnetEmaTaoFlow, SubnetEmaProtocolFlow)
  • • Signed weight and consensus computations
  • • Subnet economic smoothing factors

Fields (1)

#NameType
0bitsi128

SCALE Encoding

Rule
1 field encoded consecutively in declaration order. No field names or delimiters.
Size
sum of field sizes

Examples

Struct with 1 field = bits: i128
0x<field0>
field 0 bits: i128

Code Examples

import { TypeRegistry } from "@polkadot/types";

const registry = new TypeRegistry();

// Encode FixedI128
const value = registry.createType("FixedI128", {
  bits: 0
});
console.log("Hex:", value.toHex());

Type Parameters

Frac = UInt

Referenced By (8)

#196 (u64, FixedI128) #228 (u16, FixedI128) #395 AdminUtils::Call via sudo_set_subnet_moving_alpha.alpha#395 AdminUtils::Call via sudo_set_tao_flow_cutoff.flow_cutoff#515 Tick via fees_out_tao#515 Tick via fees_out_alpha#517 Position via fees_tao#517 Position via fees_alpha

Type Information

Type ID
187
Kind
Composite
Path
substrate_fixed::FixedI128
Runtime
v411
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