public static void main(String[] args) { double[] sigma = {3E-4, 1E-6, 2.4E-2, 6.67E-5, 1E-6, 6E-3, 4.4E-4, 1E-2, 1E-6}; double[] mu = {0.42E9, 2.27}; double alpha = 0.0; Sampler sampler = new Sampler(mu, sigma, alpha); double[][] M = sampler.getCovMat(); System.out.println("The Covirance Matrix is:"); sampler.printMatrix(M); double[][] A = sampler.getCholDecompA(); System.out.println("The decomposed Matrix A is"); sampler.printMatrix(A); try { File file = new File("/Users/Weizheng/Documents/JavaWorkPlace/CLS_MCIntegrator/output.txt"); // if file doesnt exists, then create it if (!file.exists()) { file.createNewFile(); } else { file.delete(); file.createNewFile(); } PrintWriter fw = new PrintWriter(file); long startTime = System.currentTimeMillis(); for (int i = 0; i < 1E3; i++) { double[] MultiNormalVector = sampler.nextMultiNormalVector(); // for(double a:MultiNormalVector ){ // fw.printf("%4.2e ", a); // } // fw.println(""); } fw.close(); long endTime = System.currentTimeMillis(); System.out.println("That took " + (endTime - startTime) + " milliseconds"); } catch (IOException e) { e.printStackTrace(); } }