# Function eigs Compute eigenvalue and eigenvector of a real symmetric matrix. Only applicable to two dimensional symmetric matrices. Uses Jacobi Algorithm. Matrix containing mixed type ('number', 'bignumber', 'fraction') of elements are not supported. Input matrix or 2D array should contain all elements of either 'number', 'bignumber' or 'fraction' type. For 'number' and 'fraction', the eigenvalues are of 'number' type. For 'bignumber' the eigenvalues are of ''bignumber' type. Eigenvectors are always of 'number' type. ## Syntax ```js math.eigs(x) ``` ### Parameters Parameter | Type | Description --------- | ---- | ----------- `x` | Array | Matrix | Matrix to be diagonalized ### Returns Type | Description ---- | ----------- {values: Array, vectors: Array} | {values: Matrix, vectors: Matrix} | Object containing eigenvalues (Array or Matrix) and eigenvectors (2D Array/Matrix with eigenvectors as columns). ## Examples ```js const H = [[5, 2.3], [2.3, 1]] const ans = math.eigs(H) // returns {values: [E1,E2...sorted], vectors: [v1,v2.... corresponding vectors as columns]} const E = ans.values const U = ans.vectors math.multiply(H, math.column(U, 0)) // returns math.multiply(E[0], math.column(U, 0)) const UTxHxU = math.multiply(math.transpose(U), H, U) // rotates H to the eigen-representation E[0] == UTxHxU[0][0] // returns true ``` ## See also [inv](inv.md)