lib 1400579 // ejml-core
lib 1400580 // ejml-ddense

import org.ejml.data.*;
import org.ejml.dense.row.*;
import org.ejml.dense.row.decomposition.eig.*;

static Complex[] eigenvaluesOfSymmetricMatrix(double[][] matrixData) {
  var matrix = new DMatrixRMaj(matrixData);

  var evd = new SymmetricQRAlgorithmDecomposition_DDRM(false); // false = don't need vectors
  if (!evd.decompose(matrix))
    null;
  
  int n = evd.getNumberOfEigenvalues();
  Complex[] eigenvalues = new[n];
  for i to n: {
    var v = evd.getEigenvalue(i);
    eigenvalues[i] = Complex(v.real, v.imaginary);
  }
  ret eigenvalues;
}