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Barycentric Node Weight Common Scale Invariance Tool

Scale one barycentric weight by the same nonzero factor used for every node; normalized interpolation is invariant.

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Description

Require nonzero commonScale, multiply one weight by it, and return invariant true.

Barycentric interpolation expresses a polynomial as a quotient of weighted sums. Standard weights depend on node differences; common nonzero scaling cancels only when applied consistently to the full quotient.

Require nonzero commonScale, multiply one weight by it, and return invariant true.

When to use this tool

Use Barycentric Node Weight Common Scale Invariance when you need one barycentric weight, sign, or influence component.

How to use the tool and how it works

  1. Enter weight, commonScale. Use the units and conventions below.
  2. Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
  3. Read scaledWeight, invariant. Inspect invariant before interpreting the associated values.

Require nonzero commonScale, multiply one weight by it, and return invariant true.1

In the barycentric quotient, the same weights appear in the numerator and denominator. A common nonzero multiplier cancels across the complete formula; changing only one node weight generally does not.2

Input fieldMeaning and unitsAccepted input
weightWeightRequired. Finite number.
commonScaleCommon ScaleRequired. Finite number.
Output fieldInterpretationReturned shape
scaledWeightScaled WeightRequired. Finite number.
invariantInvariantRequired. Boolean.
json
{
  "input": {
    "weight": 2,
    "commonScale": -3
  },
  "output": {
    "scaledWeight": -6,
    "invariant": true
  }
}

Limitations and assumptions

  • Invariance concerns the complete barycentric quotient only when every weight shares that scale; this tool does not verify or evaluate the full quotient.
  • 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 a complete barycentric evaluator with exact-node handling and appropriate weight scaling for actual interpolation.

References

  1. Calculation and input contract: interpolation/barycentric-node-weight-common-scale-invariance — tool.io

  2. Barycentric Lagrange Interpolation — Jean-Paul Berrut and Lloyd N. Trefethen / SIAM Review

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