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Thread: Ok Im stuck where has my code went wrong

  1. #1
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    Default Ok Im stuck where has my code went wrong

    Im stuck I am trying to write a program that takes a chi squared test, however I get this error


    mixing_up.java:130: array required, but double found
    A2_CAL[I] = ALPHA2[I] / (1 + DELTA[J]*DELTA[J])*(B2F21 + 2*DELTA[J]*B2F22 + B2F23*Math.pow(DELTA[J],2));


    I dont know why, as I have declared delta as an array. Anyhelp would be appreciated.

    import javax.swing.JOptionPane; 
    import java.io.*;
    import java.util.*;
    import java.text.DecimalFormat;
    import java.util.logging.Level;
    import java.util.logging.Logger;
    import javax.swing.*;
    import java.io.File;
    import static java.lang.Math.*;
     
     
    public class mixing_up
    {
    public static void main(String[] args)
    {
    DecimalFormat fmt = new DecimalFormat("0.###E0"); //number of decimal places 3 and in scientific format
     
     
    JOptionPane.showMessageDialog (null, "<html> This program calculates the mixing ratio using the chi squared test");
    JOptionPane.showMessageDialog (null, "Written by me");
     
     
     StringBuilder results = new StringBuilder();
    String s,t,u,v,w,x,y,z,m,j,l,o,ap,bb,lo,q;
    s = JOptionPane.showInputDialog("Enter the value of alpha2: "); 
    double ALPHA2 = Double.parseDouble(s);
     
    t = JOptionPane.showInputDialog("Enter the value of alpha2 error: ");
    double DALPHA2 = Double.parseDouble(t);
     
    u= JOptionPane.showInputDialog(null,"Enter the value of alpha4: ");
    double ALPHA4 = Double.parseDouble(u);
     
    v= JOptionPane.showInputDialog("Enter the value of alpha4 error: ");
    double DALPHA4 = Double.parseDouble(v);
     
    w = JOptionPane.showInputDialog("Enter the value of A2/A0:");
    double A2_EXP = Double.parseDouble(w);
     
    x = JOptionPane.showInputDialog("Enter the value of A2/A0 error: ");
    double DA2 = Double.parseDouble(x);
     
    y = JOptionPane.showInputDialog("Enter the value of A4/A0: ");
    double A4_EXP = Double.parseDouble(y);
     
     
    z= JOptionPane.showInputDialog("Enter the value of A4/A0 error: ");
    double DA4 = Double.parseDouble(z);
     
     
    m =JOptionPane.showInputDialog("Enter the value of B2F2 (DD, 11): ");
    double B2F21 = Double.parseDouble(m);
     
    j =JOptionPane.showInputDialog("Enter the value of B2F2 (DQ, 12): ");
    double B2F22 = Double.parseDouble(j);
     
    l =JOptionPane.showInputDialog("Enter the value of B2F2 (QQ, 22): ");
    double B2F23 = Double.parseDouble(l);
     
    o =JOptionPane.showInputDialog("Enter the value of B4F4 (QQ): ");
    double B4F4 = Double.parseDouble(o);
     
    ap =JOptionPane.showInputDialog("Enter the lower limit for arctan(delta) (-90.lt.delta): ");
    double DL = Double.parseDouble(ap);
     
    bb =JOptionPane.showInputDialog("Enter the upper limit for arctan(delta) (delta.lt+90): ");
    double DU = Double.parseDouble(bb);
     
    lo =JOptionPane.showInputDialog("Enter the number of steps for arctan(delta) max 1000: ");
    double N = Double.parseDouble(lo);
     
    q =JOptionPane.showInputDialog("Please select from the following: To fit A2/A0 press 1. To fit A4/A0 press 2. To fit A2/A0 and A4/A0 press 3. ");
    double r = Double.parseDouble(q);
     
    double  CHI_UP = 1000000000;
    double  CHI_LOW = 1000000000;
    double  CHI_CENTER = 1000000000;
    double  Lun = 6;
    double ALPHA2_1 = ALPHA2-DALPHA2;
    double ALPHA2_3 = ALPHA2+DALPHA2;
    double ALPHA4_1 = ALPHA4-DALPHA4;
    double ALPHA4_3 = ALPHA4+DALPHA4;
    double [] A2_CAL;
    A2_CAL = new double[3];
    double [] DELTA;
    DELTA = new double[1001];
    double [] ANGLE;
    ANGLE = new double[1001];
    double [] ANGLE2;
    ANGLE2 = new double[1001];
    double []A4_CAL;
    A4_CAL = new double[3];
    double [] X2;
    X2 = new double[3];
    double[] LOGX2;
    LOGX2 = new double[1001];
    double[] CHI_2;
    CHI_2 = new double[1001]; 
    double DELTA_LOW; 
    double DELTA_UP; 
    double ANGLE_LOW; 
    double ANGLE_UP; 
    double DELTA_E_LOW; 
    double DELTA_E_UP; 
    double ANGLE_E_LOW; 
    double ANGLE_E_UP; 
    double CHI_E_LOW; 
    double CHI_E_UP; 
    double CHI_ERROR; 
    double DELTA_CENTER; 
    double ANGLE_CENTER; 
    double J_LOW; 
    double J_UP; 
    double J_CENTER;
     
     
     
    if (r == 1) {
    // put A2 only code here
    for(int J=1; J< N; J++)
    {
     
    ANGLE[J]= DL + (J-1)*((DU - DL)/N);
    ANGLE2[J] = ANGLE[J]/57.297;
    DELTA[J] =  Math.tan(ANGLE2[J]); 
     
     
    for(int I=1;  I < 4; I++)
    {
    A2_CAL[I] = ALPHA2[I] / (1 + DELTA[J]*DELTA[J])*(B2F21 + 2*DELTA[J]*B2F22 + B2F23*Math.pow(DELTA[J],2));
     
    X2[I] = Math.pow(A2_CAL[I] - A2_EXP,2) / Math.pow(DA2,2);
     
    }
     
    CHI_2[J] = X2[2];       
    LOGX2[J] = Math.log10(X2[2]);
     
    if (CHI_2[J] < CHI_CENTER)
    {
    CHI_CENTER = CHI_2[J];
    ANGLE_CENTER = ANGLE[J];
    DELTA_CENTER = DELTA[J];
    }
     
     
    if (X2[1] < CHI_LOW) 
    { 
    CHI_LOW = X2[1];
    ANGLE_UP = ANGLE[J];
    DELTA_UP = DELTA[J];
    }
     
    if (X2[3] < CHI_UP) 
    { 
    CHI_UP = X2[3];
    ANGLE_LOW = ANGLE[J];
    DELTA_LOW = DELTA[J];
    }
    }
     
    results.append("The values of X2(2) chi central i.e chi squared minimum " + fmt.format(CHI_CENTER) +  "");
    results.append('\n');
    results.append("The value of X2(1) chi squared lower limit is " + fmt.format(CHI_LOW) +  "");
    results.append('\n');
    results.append("The value of X2(3) chi squared upper limit is" + fmt.format(CHI_UP) +  "");
    results.append('\n');
    results.append("The value of Delta for chi central is " + fmt.format(DELTA_CENTER) +  "");
    results.append('\n');
    results.append("The value of Angle for chi central is " + fmt.format(ANGLE_CENTER) +  "");
     
     
    FileWriter resultFile = null;
     try {
                resultFile = new FileWriter("mixing_ratio.dat");
                resultFile.write(results.toString());
     
     
    	    resultFile.close();
            } catch (IOException ex) {
                Logger.getLogger(mixing_up.class.getName()).log(Level.SEVERE, null, ex);
            }
    	JOptionPane.showMessageDialog (null, "The values of X2(2) chi central i.e chi squared minimum " + fmt.format(CHI_CENTER) +  ""); 
    	JOptionPane.showMessageDialog (null, "The value of X2(1) chi squared lower limit is " + fmt.format(CHI_LOW) +  "");         
    	JOptionPane.showMessageDialog (null, "The value of X2(3) chi squared upper limit is " + fmt.format(CHI_UP) +  "");
    	JOptionPane.showMessageDialog (null, "The value of Delta for chi central is " + fmt.format(DELTA_CENTER) +  "" );
    	JOptionPane.showMessageDialog (null, "The value of Angle for chi central is " + fmt.format(ANGLE_CENTER) +  "" );
    	JOptionPane.showMessageDialog (null, "The value of chi squared central for a given value of delta is" + fmt.format(DELTA) +  "" );
     
     
     
     
    	JOptionPane.showMessageDialog (null, "Thank you for using the program the results are saved in mixing_ratio.dat" ); 
    	JOptionPane.showMessageDialog (null, "Have a Nice Day" ); 
     
     
    }
    }
     }


  2. #2
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    Default Re: Ok Im stuck where has my code went wrong

    double ALPHA2 
    A2_CAL[I] = ALPHA2[I]
    Can you spot the problem?
    Improving the world one idiot at a time!

  3. #3
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    Default Re: Ok Im stuck where has my code went wrong

    Ahh, Ok i got it, thanks buddy

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