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Matrix Unit Lower Entry Implicit Value Tool

Compute matrix unit lower entry implicit value from explicit bounded inputs.

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Description

Return one on the diagonal, zero above it, and storedValue below it.

Triangular storage can leave structural zeros and unit diagonals implicit. Solving or inverting requires usable diagonal entries, but a diagonal threshold alone does not measure conditioning.

Return one on the diagonal, zero above it, and storedValue below it.

When to use this tool

Use Matrix Unit Lower Entry Implicit Value when you need a triangular-entry convention or pivot diagnostic.

How to use the tool and how it works

  1. Enter row, column, storedValue. 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 value, implicit. Inspect implicit before interpreting the associated values.

Return one on the diagonal, zero above it, and storedValue below it. Mark implicit for diagonal and upper entries.1

Input fieldMeaning and unitsAccepted input
rowRowRequired. Safe integer; minimum 0.
columnColumnRequired. Safe integer; minimum 0.
storedValueStored ValueRequired. Finite number.
Output fieldInterpretationReturned shape
valueValueRequired. Finite number.
implicitImplicitRequired. Boolean.
json
{
  "input": {
    "row": 2,
    "column": 2,
    "storedValue": 9
  },
  "output": {
    "value": 1,
    "implicit": true
  }
}

Limitations and assumptions

  • Indices are nonnegative but no matrix size is supplied; this represents a unit-lower storage convention rather than reading a matrix.
  • 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 stable triangular solver and a condition estimate for a complete numerical solution.

References

  1. Calculation and input contract: matrix/matrix-unit-lower-entry-implicit-value — tool.io

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