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Matrix Eigenvalues Calculator

Eigenvalues and eigenvectors of a small real matrix via the characteristic polynomial. Same engine as Linear System. Not a CAS. Runs locally.

Instant result
Result
—

Enter values to calculate.

Inputs—
Mode—
Formula—
Trust summary CVP VERIFIED · CVP protocol 1.0.0-proposed · Core assurance · all published modes
Input interpretation
Enter values to calculate.
Result
—
Verified scope
all published modes
Assurance
Core
Declared partition coverage
PASS · 19/19 declared partitions (solve, det, inverse, multiply, transpose, rank, eigen, lu, chol, qr, svd, lstsq, rref, condition, nullspace, columnspace, rowspace, leftnullspace, invalid-domain) · Matrix
Known limitations
  • Core CVP does not include live graph, viewport, or pointer interaction.
Model
Eigenvalues and eigenvectors for order 2–3 (engine up to 4).
Scope
Real matrices; eigenvalues may be complex
Verification
Engine tested · Specification checked · v1.14.0 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Core assurance · all published modes· View Manifest · CVP overview · Specification
Versions
Calculation 1.14.0 · CVP protocol 1.0.0-proposed · Evidence 2026-09-22.la-hardening-lu-svd
Verification revision
2026-09-22.la-hardening-lu-svd · 7/7 property · digest 7307c47e0dc1
Legacy regression
58/58 tests · Production surface contract 5/5
Trust layers
Verification VERIFIED · Production CURRENT · Overall CVP state: VERIFIED under CVP 1.0.0-proposed
Reference
O1 model · O2 expected_values · O2 numerical_behavior
Interfaces
PASS · UI (SSR) / REST / MCP — ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
Supplemental domain review
Not performed
Named expert review
Not performed
CVP suite
24/24 golden · 8/8 CVP boundary · 14/14 invalid · 7/7 property · 9/9 cross-interface · 2/2 cross-calculator · 5/5 CVP contract · Manifest
Specification basis
  • ISO 80000-2:2019 Quantities and units — Mathematics
Specification basis
Evidence
29 legacy golden · 6 legacy boundary · legacy regression suite · 24/24 oracle-backed golden · 14/14 invalid · Artifact integrity PASS
This calculator CURRENT · Public schema 1.14.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓
Semantic contract
PASS
Full verification

Manifest identity, reference classes, interfaces, suite, and production records.

Formulas

Core equations used by this calculator.

Characteristic polynomialp(λ) = det(A − λI)
Eigenvector(A − λI)v = 0, ‖v‖₂ = 1
iFaddeev–LeVerrier char poly; roots via math.polynomial.roots (quadratic closed form, then Durand–Kerner). Seed path for order ≤ 4 — not Hessenberg + QR iteration. Not SVD. Not a CAS. Complex eigenvalues of real matrices are returned as re/im pairs. Float64.

How to use

1

Enter a square matrix

2×2 or 3×3. Larger composition lives at /workspace/matrix.

2

Read λ and v

Each pair satisfies Av ≈ λv within residual_max. Ill-conditioned matrices warn.

Example calculations

Common configurations with formula and result.

ϟ

Diagonal

diag(2, 3)

2, 3
2, 3
ϟ

Rotation

[[0,−1],[1,0]]

±i
±i

Matrix Eigenvalues calculator specification

Version 1.14.0 · Engine tested

Calculation status

Review policy · Evidence

Definition
λ is an eigenvalue of A when det(A − λI) = 0. This page is a discovery surface on the linear-algebra engine (mode=eigen). LU, QR, det, inverse, rank, and Ax=b share the same capability.
What it calculates
Eigenvalues and eigenvectors for order 2–3 (engine up to 4).
Inputs
  • order
  • a11…
Outputs
  • eigenvalues
  • eigenvectors
  • residual_max
  • condition_number
Formula
det(A − λI) = 0
Assumptions
  • Real matrices; eigenvalues may be complex
  • Order ≤ 4
  • Planar ℝ² figure when order=2; order 3+ omits it
  • Float64
  • Not a CAS
  • Not SVD
Units
  • dimensionless
Boundary conditions
  • defective matrix → fewer independent eigenvectors + warning
  • unknown mode (including jordan-form) → INVALID_MODE
Example
diag(2,3) → λ=2,3
Validation cases

2 published on this page · 58/58 tests · Production surface contract 5/5 · View evidence

  • order=2 a11=2 a12=0 a21=0 a22=3 → eigenvalues 2, 3
  • order=2 a11=0 a12=-1 a21=1 a22=0 → ±i
Specification basis
  • ISO 80000-2:2019 Quantities and units — Mathematics
Calculation version
1.14.0

Other calculators in this family: Cholesky Factorization Calculator, Column Space Calculator, Condition Number Calculator, Least Squares Calculator, Left Nullspace Calculator, Linear System Calculator, LU Factorization Calculator, Matrix Determinant Calculator . Explore all Linear Algebra.

→ Cholesky Factorization Calculator Lower Cholesky factorization of a small real symmetric positive-definite matrix. Same engine as Linear System. Not LU. Not a CAS. Runs locally. › → Column Space Calculator Column space (image) of a small real square matrix from RREF pivot columns. Same engine as Linear System. Trivial image is {0}. Left-nullspace is a sibling. Runs locally. › → Condition Number Calculator κ₁(A) = ‖A‖₁ ‖A⁻¹‖₁ for a small real square matrix. Same engine as Linear System. Singular matrices return infinite. Not a 2-norm product. Runs locally. › → Least Squares Calculator Linear least squares for a small real matrix, square or rectangular. Full column rank uses QR; otherwise SVD. Same engine as Linear System. Not Statistics regression. Runs locally. › → Left Nullspace Calculator Left-nullspace (cokernel) of a small real square matrix as ker(Aᵀ). Same engine as Linear System. Trivial left kernel is {0}. Not Jordan form. Runs locally. › → Linear System Calculator Solve small linear systems Ax = b, plus det, inverse, rank, LU, Cholesky, QR, SVD, least squares, RREF, condition number, nullspace, column space, rowspace, left-nullspace, and eigenvalues. Same engine as the matrix workspace. Not a CAS. Runs locally. › → LU Factorization Calculator Doolittle LU factorization with partial pivoting for a small real matrix. Same engine as Linear System. Not a CAS. Runs locally. › → Matrix Determinant Calculator Determinant of a small real matrix. Same engine as Linear System and the matrix workspace. Not a CAS. Runs locally. ›

Frequently asked questions

Key distinctions behind the calculation.

Is this a second eigen solver?

No. It is mode=eigen on math.linear_algebra, the same engine as /calc/math/linear-system and /workspace/matrix.

Are complex eigenvalues supported?

Yes for real matrices. A 90° rotation returns ±i. SVD stays out of this seed.