// ac_analysis.java  simple AC circuit analysis
//                   java -cp . ac_analysis < ac_analysis.dat
//
// Label the circuit nodes consecutively, zero 0  must be ground
// Every node must be a part of a current loop and the circuit
// must be connected. The input is:
//
// R i j value_in_ohm     resister between node i and node j
// C i j value_in_farad   capacitor between node i and node j
// L i j value_in_henry   inductor between node i and node j
// I i j value_in_amp     current source, flow from node i to node j
// V i j value_in_volts value_in_ohm  voltage to current source
// A i j a b value_gain   voltage i to j times gain is current a to b
// F value_in_hertz_initial  value_in_hertz_maximum  factor
//   frequency is set to initial value and circuit analyzed,
//   node voltages are printed in complex,
//   frequency is multiplied by 'factor' and analysis repeated,
//   the program exits when frequency is greater than maximum
//
// A voltage source V must have a series resistor R. This is coded
// for input as two lines  I i j value_V/R
//                         R i j value_R      node j is positive
// A value of zero is not allowed for any component.
// Solutions may not exists for some circuits at some frequencies.
//
 
// Method: Construct admittance matrix Y and current source vector I
// Solve system of equations Y*V=I for node voltages V
// The subscript zero is never used in the Y matrix, I vector or V vector
// I i j V  results in  I(i)=I(i)-V  I(j)=I(j)+V
// R i j V  results in  Y(i,i)=Y(i,i)+1/V  Y(j,j)=Y(j,j)+1/V
//                      Y(i,j)=Y(i,j)-1/v  Y(j,i)=Y(j,i)-1/V
// C i j V  results in YC = (0,2.0*Pi*F*V) complex number
//                      Y(i,i)=Y(i,i)+YC   Y(j,j)=Y(j,j)+YC
//                      Y(i,j)=Y(i,j)-YC   Y(j,i)=Y(j,i)-YC
// L i j V  results in YL = (0,-1.0/(2*Pi*F*V)) complex number
//                      Y(i,i)=Y(i,i)+YL   Y(j,j)=Y(j,j)+YL
//                      Y(i,j)=Y(i,j)-YL   Y(j,i)=Y(j,i)-YL
// A a i V  results in  Y(a,i)=Y(a,i)+V other entries for a,j(-) b,i(-) b,j
// The Y matrix must be built for every frequency.
// The matrix equation is solved for the node voltages for each frequency.
//
 
import java.io.*;

class ac_analysis
{
  int n;
  int n_input; // for storing input for various frequencies
  double F, F_initial, F_final, F_factor;
  char type[] = new char[100];
  int  node1[] = new int[100];
  int  node2[] = new int[100];
  double value[] = new double[100];
  boolean debug = false;
  
  ac_analysis()
  {
    double val, TPIF;
    Complex cval;
    int ii, jj;

    System.out.println("ac_analysis running");
    Complex i1 = new Complex(0.0,1.0);

    System.out.println("ac_analysis about to read input");
    // no read routine, just fill in circuit data
    F_initial = 1.0;
    F_final   = 1.0;
    F_factor  = 2.0;
    n = 0;  
    n_input = 0;
    try
    {
      ReadInput();
    }
    catch(IOException exception)
    {
      System.out.println(exception);
      return;
    }
    n_input++;
    System.out.println("number of nodes="+n+", components="+n_input);
    
    if(n==0 || n_input<2)
    {
      System.out.println("no recognizable circuit input");
      return;
    }
    // set up arrays
    Complex Y[][] = new Complex[n][n];
    Complex I[] = new Complex[n];
    Complex V[] = new Complex[n];

    F = F_initial;
    while(F<=F_final)
    {
      System.out.println("ac_analysis about to build Y and I");
      TPIF = 6.28*F; // radians per second
      ComplexMatrix.zero(Y);
      ComplexMatrix.zero(V);
      ComplexMatrix.zero(I);
      for(int i=0; i<n_input; i++)
      {
        // type N and F not stored
        if(type[i]=='R' || type[i]=='r')
        {
          ii = node1[i]-1;
          jj = node2[i]-1;
          val = 1.0/value[i];
          if(debug) System.out.println(i+" R "+ii+" "+jj+" "+val);
          if(ii>=0) Y[ii][ii]=Y[ii][ii].add(val);
          if(jj>=0) Y[jj][jj]=Y[jj][jj].add(val);
          if(ii>=0 && jj>=0) Y[ii][jj]=Y[ii][jj].subtract(val);
          if(ii>=0 && jj>=0) Y[jj][ii]=Y[jj][ii].subtract(val);
        }
        else if(type[i]=='L' || type[i]=='l')
        {
          ii = node1[i]-1;
          jj = node2[i]-1;
          cval = (i1.divide(TPIF*value[i])).negate();
          if(debug) System.out.println(i+" L "+ii+" "+jj+" "+cval);
          if(ii>=0) Y[ii][ii]=Y[ii][ii].add(cval);
          if(jj>=0) Y[jj][jj]=Y[jj][jj].add(cval);
          if(ii>=0 && jj>=0) Y[ii][jj]=Y[ii][jj].subtract(cval);
          if(ii>=0 && jj>=0) Y[jj][ii]=Y[jj][ii].subtract(cval);
        }
        else if(type[i]=='C' || type[i]=='c')
        {
          ii = node1[i]-1;
          jj = node2[i]-1;
          cval = i1.multiply(TPIF*value[i]);
          if(debug) System.out.println(i+" C "+ii+" "+jj+" "+cval);
          if(ii>=0) Y[ii][ii]=Y[ii][ii].add(cval);
          if(jj>=0) Y[jj][jj]=Y[jj][jj].add(cval);
          if(ii>=0 && jj>=0) Y[ii][jj]=Y[ii][jj].subtract(cval);
          if(ii>=0 && jj>=0) Y[jj][ii]=Y[jj][ii].subtract(cval);
        }
        else if(type[i]=='I' || type[i]=='i')
        {
          ii = node1[i]-1;
          jj = node2[i]-1;
          val = value[i];
          if(debug) System.out.println(i+" I "+ii+" "+jj+" "+val);
          if(ii>=0) I[ii]=I[ii].subtract(val);
          if(jj>=0) I[jj]=I[jj].add(val);
        }
        else if(type[i]=='A' || type[i]=='a')
        {
          ii = node1[i]-1;
          jj = node2[i]-1;
          val = value[i];
          if(debug) System.out.println(i+" A "+ii+" "+jj+" "+val);
          if(jj>=0 && ii>=0) Y[ii][jj]=Y[ii][jj].add(val);
        }
      }
      if(debug || F==F_initial)
      {
        System.out.println("admittance matrix Y");
        ComplexMatrix.print(Y);
        System.out.println("current vector I");
        ComplexMatrix.print(I);
      }
      ComplexMatrix.solve(Y, I, V);
      System.out.println("node voltages at frequency = "+F);
      for(int i=0; i<n; i++)
      {
        System.out.println("V["+(i+1)+"]="+V[i]);
      }
      F = F * F_factor;
    } // end while loop on frequency
  } // end constructor ac_analysis
  
  void ReadInput() throws IOException
  {
    try
    {
      // BufferedReader in = new BufferedReader(new FileReader("bank.dat"));
      BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
      String input_line;
      String name;
      double amount, amount2;
      int node;
      int nodev1, nodev2, nodea1, nodea2;
      int len;
      int index;
      int last;
   
      if(debug) System.out.println("ReadInput running");
      input_line = in.readLine(); // first read before  'while'
      while(input_line != null)
      {
        System.out.println("input: "+input_line);
        len = input_line.length();
        if(len<6) continue; // too short to be a valid input
        name = input_line.substring(0,1); // type
        if(debug) System.out.println("name="+name);
        if(name.equalsIgnoreCase("f")) // 3 frequencies
        {
          index = input_line.indexOf(' ',1); // F_initial
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          amount = Double.parseDouble(input_line.substring(index+1,last));
          if(debug) System.out.println("amount="+amount);
          F_initial = amount;
          index = input_line.indexOf(' ',last); // F_final
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          amount = Double.parseDouble(input_line.substring(index+1,last));
          if(debug) System.out.println("amount="+amount);
          F_final = amount;
          index = input_line.indexOf(' ',last); // F_factor
          if(debug) System.out.println("index="+index);
          last = len;
          if(debug) System.out.println("last="+last);
          amount = Double.parseDouble(input_line.substring(index+1,last));
          if(debug) System.out.println("amount="+amount);
          F_factor = amount;
          input_line = in.readLine();
          continue;
        }
        if(name.equalsIgnoreCase("a")) // amplifier
        {
          index = input_line.indexOf(' ',1); // nodev1
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          nodev1 = Integer.parseInt(input_line.substring(index+1,last));
          if(debug) System.out.println("nodev1="+nodev1);
          if(nodev1>n) n = nodev1;
          index = input_line.indexOf(' ',last); // nodev2
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          nodev2 = Integer.parseInt(input_line.substring(index+1,last));
          if(debug) System.out.println("nodev2="+nodev2);
          index = input_line.indexOf(' ',last); // nodea1
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          nodea1 = Integer.parseInt(input_line.substring(index+1,last));
          if(debug) System.out.println("nodea1="+nodea1);
          index = input_line.indexOf(' ',last); // nodea2
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          nodea2 = Integer.parseInt(input_line.substring(index+1,last));
          if(debug) System.out.println("nodea2="+nodea2);
          if(nodea2>n) n = nodea2;
          index = input_line.indexOf(' ',last); // amount
          if(debug) System.out.println("index="+index);
          last = len;
          if(debug) System.out.println("last="+last);
          amount = Double.parseDouble(input_line.substring(index+1,last));
          if(debug) System.out.println("amount="+amount);
          if(nodea1!=0 && nodev1!=0)
          {
            n_input++;
            type[n_input] = 'A';
            node1[n_input] = nodea1;
            node2[n_input] = nodev1;
            value[n_input] = amount;
          }
          if(nodea1!=0 && nodev2!=0)
          {
            n_input++;
            type[n_input] = 'A';
            node1[n_input] = nodea1;
            node2[n_input] = nodev2;
            value[n_input] = -amount;
          }
          if(nodea2!=0 && nodev1!=0)
          {
            n_input++;
            type[n_input] = 'A';
            node1[n_input] = nodea2;
            node2[n_input] = nodev1;
            value[n_input] = -amount;
          }
          if(nodea2!=0 && nodev2!=0)
          {
            n_input++;
            type[n_input] = 'A';
            node1[n_input] = nodea2;
            node2[n_input] = nodev2;
            value[n_input] = amount;
          }
        }

	else if(name.equalsIgnoreCase("v")) // voltage source to current
        {
          if(debug) System.out.println("found V");
          index = input_line.indexOf(' ',1); // nodev1
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          nodev1 = Integer.parseInt(input_line.substring(index+1,last));
          if(debug) System.out.println("nodev1="+nodev1);
          if(nodev1>n) n = nodev1;
          index = input_line.indexOf(' ',last); // nodev2
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          nodev2 = Integer.parseInt(input_line.substring(index+1,last));
          if(debug) System.out.println("nodev2="+nodev2);
          if(nodev2>n) n = nodev2;
          index = input_line.indexOf(' ',last); // amount
          if(debug) System.out.println("index="+index);
          last = input_line.indexOf(' ',index+1);
          if(debug) System.out.println("last="+last);
          amount = Double.parseDouble(input_line.substring(index+1,last));
          if(debug) System.out.println("amount="+amount);
          index = input_line.indexOf(' ',last); // amount2
          if(debug) System.out.println("index="+index);
          last = len;
          if(debug) System.out.println("last="+last);
          amount2 = Double.parseDouble(input_line.substring(index+1,last));
          if(debug) System.out.println("amount2="+amount2);
          n_input++;
          type[n_input] = 'I';
          node1[n_input] = nodev1;
          node2[n_input] = nodev2;
          value[n_input] = amount/amount2;
	  n_input++;
	  type[n_input] = 'R';
          node1[n_input] = nodev1;
          node2[n_input] = nodev2;
          value[n_input] = amount2;
        }

        if(name.equalsIgnoreCase("i")) // current source
        {
          if(debug) System.out.println("found I");
          n_input++;
          type[n_input] = 'I';
        }
        else if(name.equalsIgnoreCase("r")) // resistor
        {
          if(debug) System.out.println("found R");
          n_input++;
          type[n_input] = 'R';
        }
        else if(name.equalsIgnoreCase("c")) // capacitor
        {
          if(debug) System.out.println("found C");
          n_input++;
          type[n_input] = 'C';
        }
        else if(name.equalsIgnoreCase("l")) // inductor
        {
          if(debug) System.out.println("found L");
          n_input++;
          type[n_input] = 'L';
        }
        else // not recognized
        {
          if(debug) System.out.println("unrecognized input");
          input_line = in.readLine();
          continue;
        }
        index = input_line.indexOf(' ',1); // node1
        if(debug) System.out.println("index="+index);
        last = input_line.indexOf(' ',index+1);
        if(debug) System.out.println("last="+last);
        node = Integer.parseInt(input_line.substring(index+1,last));
        if(debug) System.out.println("node="+node);
        if(node>n) n = node;
        node1[n_input] = node;
        index = input_line.indexOf(' ',last); // node2
        if(debug) System.out.println("index="+index);
        last = input_line.indexOf(' ',index+1);
        if(debug) System.out.println("last="+last);
        node = Integer.parseInt(input_line.substring(index+1,last));
        if(debug) System.out.println("node="+node);
        if(node>n) n = node;
        node2[n_input] = node;        
        index = input_line.indexOf(' ',last); // amount
        if(debug) System.out.println("index="+index);
        last = len;
        if(debug) System.out.println("last="+last);
        amount = Double.parseDouble(input_line.substring(index+1,last));
        if(debug) System.out.println("amount="+amount);
        value[n_input] = amount;
        if(debug) System.out.println();
  
        input_line = in.readLine(); // tested for "null" in 'while'
      } // end while
    } // end try
    catch(IOException exception)
    {
      System.out.println(exception);
      return;
    }
    System.out.println("ReadInput finished");
  } // end ReadInput
  
  public static void main(String args[])
  {
    new ac_analysis();
  }
} // end ac_analysis.java