module.exports = adjoint

/**
 * Calculates the adjugate of a mat2
 *
 * @alias mat2.adjoint
 * @param {mat2} out the receiving matrix
 * @param {mat2} a the source matrix
 * @returns {mat2} out
 */
function adjoint(out, a) {
  // Caching this value is nessecary if out == a
  var a0 =  a[0]
  out[0] =  a[3]
  out[1] = -a[1]
  out[2] = -a[2]
  out[3] =  a0

  return out
}