# Function eye Create a 2-dimensional identity matrix with size m x n or n x n. The matrix has ones on the diagonal and zeros elsewhere. ## Syntax ```js math.eye(n) math.eye(n, format) math.eye(m, n) math.eye(m, n, format) math.eye([m, n]) math.eye([m, n], format) ``` ### Parameters Parameter | Type | Description --------- | ---- | ----------- `size` | ...number | Matrix | Array | The size for the matrix `format` | string | The Matrix storage format ### Returns Type | Description ---- | ----------- Matrix | Array | number | A matrix with ones on the diagonal. ## Examples ```js math.eye(3); // returns [[1, 0, 0], [0, 1, 0], [0, 0, 1]] math.eye(3, 2); // returns [[1, 0], [0, 1], [0, 0]] var A = [[1, 2, 3], [4, 5, 6]]; math.eye(math.size(A)); // returns [[1, 0, 0], [0, 1, 0]] ``` ## See also [diag](diag.md), [ones](ones.md), [zeros](zeros.md), [size](size.md), [range](range.md)