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THE FEUTEX TOOLKIT

Bitset Versus ID List Memory

Compare a dense membership bitset with an unsorted fixed-width identifier list.

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FormulaBitset payload = Math.ceil(universe/8); Identifier list payload = members*bytes; Break-even member count = Math.ceil(Math.ceil(universe/8)/bytes)

Made for real tasks

  • Compare a dense membership bitset with an unsorted fixed-width identifier list.
Explore step-by-step workflows →

Worked example

Inputs

Possible identifiers
1000000 identifiers
Present identifiers
10000 identifiers
Bytes per identifier
4 bytes

Expected results

Bitset payload
125000 bytes
Identifier list payload
40000 bytes
Break-even member count
31250 identifiers

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Enter possible identifiers, present identifiers, bytes per identifier in the displayed units.
  2. Calculate the scenario, then compare it with measurements before changing a system.

Try this example

{
  "universe": 1000000,
  "members": 10000,
  "bytes": 4
}

Accuracy and scope

Raw payload only; lookup runtime and compressed bitmaps are not modeled.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.