/* This code is based on C code of public domain XGobi software. 

This code is provided "as is" without any warranty of any kind.  We
don't warrant, guarantee or make any representations regarding the
correctness, reliability, currentness of this code. 

We welcome your questions and comments, and request that you share any
modifications with us. 

          Sunhee Kwon
         shkwon@iastate.edu
          Dianne Cook
         dicook@iastate.edu
*/

public class Blas_j2 extends Object {

 public static double max_vec(double x[], int n) {
  double max1 = x[0]; 
  for (int i=1; i<n; i++) {
   if (x[i] > max1) {max1=x[i];}
  }
  return max1;
 }

 public static double min_vec(double x[], int n) {
  double min1 = x[0]; 
  for (int i=1; i<n; i++) {
   if (x[i] < min1) {min1=x[i];}
  }
  return min1;
 }
  
 public static double mean_fn(double x1[], int n, int rows_in_plot[]) {
  double tmpf, mean1;
  tmpf = 0.0;
  for (int i=0; i<n; i++) {
   tmpf += (x1[rows_in_plot[i]]-x1[0]);}
  mean1 = tmpf/(double)n;
  mean1 += x1[0];
  return mean1;
 }

 public static double mean_fn2(double x1[], double x2[], int n, 
                   int rows_in_plot[]) {
  double tmean, tmpf1, mean1, mean2;
  tmpf1=0.0;
  for (int i=0; i<n; i++) {
   tmpf1 += x1[rows_in_plot[i]];}
  mean1 = tmpf1/(double)n;
  tmpf1=0.0;
  for (int i=0; i<n; i++) {
   tmpf1 += x2[rows_in_plot[i]];}
  mean2 = tmpf1/(double)n;
  tmean=0.0;
  for (int i=0; i<n; i++) {
   tmean += ((x1[rows_in_plot[i]]-mean1)*(x2[rows_in_plot[i]]-mean2));}
  tmean /= ((double)n);
  tmean += (mean1*mean2);
  return tmean;
 }

 public static double mean_fn3(double x1[], double x2[], double wgts[],
      int n, int rows_in_plot[]) {
  double tmean, tmpf1, mean1, mean2, mean3;
  tmpf1 = 0.0;
  for (int i=0; i<n; i++) {
   tmpf1 += x1[rows_in_plot[i]];}
  mean1 = tmpf1/(double)n;
  tmpf1 = 0.0;
  for (int i=0; i<n; i++) {
   tmpf1 += x2[rows_in_plot[i]];}
  mean2 = tmpf1/(double)n;
  tmpf1 = 0.0;
  for (int i=0; i<n; i++) {
   tmpf1 += wgts[rows_in_plot[i]];}
  mean3 = tmpf1/(double)n;
  tmean = 0.0;
  for (int i=0; i<n; i++) {
   tmean += ((x1[rows_in_plot[i]]-mean1)*(x2[rows_in_plot[i]]-mean2)
             *wgts[rows_in_plot[i]]);}
  tmean /= ((double)n);
  tmean += (mean1*mean2);
  return tmean;
 }

 public static double mean_fn5(double x1[], double x2[], double x3[],
   double x4[], double wgts[], int n, int rows_in_plot[]) {
  double tmean;
  tmean=0.0;
  for (int i=0; i<n; i++) {
   tmean += (x1[rows_in_plot[i]]*x2[rows_in_plot[i]]*x3[rows_in_plot[i]]*
             x4[rows_in_plot[i]]*wgts[rows_in_plot[i]]);}
  tmean /= ((double)n);
  return tmean;
 }

 public static void norm(int n, double x[]) {
  double xn=0.0;
  for (int j=0; j<n; j++) {
   xn = xn+x[j]*x[j];}
  xn=Math.sqrt(xn);
  for (int j=0; j<n; j++) {
   x[j] = x[j]/xn;}
 }

 public static void mat_mult(double a[][], double b[][], double matprod[][],
   int m, int n, int p) {
  double tmpf;
  for (int i=0; i<m; i++) {
   for (int j=0; j<n; j++) {
    tmpf = 0.0;
    for (int k=0; k<p; k++) {
     tmpf += (a[k][i]*b[k][j]);}  
     matprod[j][i] = tmpf;
   }
  }
 }
 public static double inner_prod(double x1[], double x2[], int n) {
  double xip;
  xip=0.0;
  for (int j=0; j<n; j++) {
   xip = xip+x1[j]*x2[j];}
  return xip;
 }

 public static void gram_schmidt(double x1[], double x2[], int n) {
  double ip;
  ip = inner_prod(x1,x2,n);
  for (int j=0; j<n; j++) {
   x2[j] = x2[j]-ip*x1[j];}
  norm(n,x2);
 }

 public static double sq_inner_prod(double x1[], double x2[], int n) {
  double xip;
  xip=0.0;
  for (int j=0; j<n; j++) {
   xip = xip+x1[j]*x2[j];}
  return xip*xip;
 }
   

}