Hamming Distance Single Symbol Update Tool

Description

Update a Hamming count after one symbol replacement.

Discrete distances depend on the representation of symbols, sets and counts. A local mismatch or count update assumes the surrounding sequence or set bookkeeping is already correct.

Update a Hamming count after one symbol replacement.

When to use this tool

Use Hamming Distance Single Symbol Update when checking a supplied discrete-distance contribution or update.

How to use the tool and how it works

Enter distance, oldFirst, second, newFirst. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read distance, delta. Use the output convention below.

Update a Hamming count after one symbol replacement. Require nonnegative whole distance; delta is the new mismatch indicator minus the old one, and updated distance must remain nonnegative.^[1]

Input field	Meaning and units	Accepted input
distance	Distance	Required. Safe integer; minimum 0.
oldFirst	Old First	Required. Text; maximum UTF-16 length 8192.
second	Second	Required. Text; maximum UTF-16 length 8192.
newFirst	New First	Required. Text; maximum UTF-16 length 8192.

Output field	Interpretation	Returned shape
distance	Distance	Required. Safe integer.
delta	Delta	Required. Safe integer.

json

{
  "input": {
    "distance": 3,
    "oldFirst": "a",
    "second": "a",
    "newFirst": "b"
  },
  "output": {
    "distance": 4,
    "delta": 1
  }
}

Limitations and assumptions

Symbols compare literally; the original complete sequence distance is supplied, not checked.
Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Use the full sequences or sets to establish the original distance and actual operation before applying a local update.

References

Calculation and input contract: distance/hamming-distance-single-symbol-update — tool.io

Similar or alternative tools

Jaccard Distance One Intersection Update
Update Jaccard distance using supplied intersection and union changes.
Distance: Discrete Symbol Mismatch Cost
Return a literal symbol mismatch cost.