CCCSElm.java

/*    
    Copyright (C) Paul Falstad
    
    This file is part of CircuitJS1.

    CircuitJS1 is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    CircuitJS1 is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with CircuitJS1.  If not, see <http://www.gnu.org/licenses/>.
*/

package com.lushprojects.circuitjs1.client;

//import java.awt.*;
//import java.util.StringTokenizer;

    class CCCSElm extends VCCSElm {
	public CCCSElm(int xa, int ya, int xb, int yb, int f,
		      StringTokenizer st) {
	    super(xa, ya, xb, yb, f, st);
//	    exprString = CustomLogicModel.unescape(st.nextToken());
	    inputCount = 2;
//	    parseExpr();
	    setupPins();
	}
	public CCCSElm(int xx, int yy) {
	    super(xx, yy);
	    exprString = "2*i";
	    parseExpr();
//	    setupPins();
	}
	
	void setupPins() {
	    sizeX = 2;
	    sizeY = 2;
	    pins = new Pin[3];
	    pins[0] = new Pin(0, SIDE_W, "C+");
	    pins[1] = new Pin(1, SIDE_W, "C-");
	    pins[1].output = true;
	    pins[2] = new Pin(0, SIDE_E, "O+");
	    pins[2].output = true;
	    pins[3] = new Pin(1, SIDE_E, "O-");
	    exprState = new ExprState(1);
	}
	String getChipName() { return "CCCS"; } 
	void stamp() {
	    // voltage source (0V) between C+ and C- so we can measure current
            int vn1 = pins[1].voltSource;
	    sim.stampVoltageSource(nodes[0], nodes[1], vn1, 0);
	    
            sim.stampNonLinear(nodes[2]);
            sim.stampNonLinear(nodes[3]);
	}

	double lastCurrent;
	
        void doStep() {
            // no current path?  give up
            if (broken) {
        	pins[inputCount].current = 0;
        	pins[inputCount+1].current = 0;
        	// avoid singular matrix errors
        	sim.stampResistor(nodes[inputCount], nodes[inputCount+1], 1e8);
        	return;
            }

            // converged yet?
//            double limitStep = getLimitStep()*.1;
            double convergeLimit = getConvergeLimit()*.1;
            
            double cur = pins[1].current;
            if (Math.abs(cur-lastCurrent) > convergeLimit) {
        	sim.converged = false;
//        	if (Math.abs(cur-lastCurrent) > limitStep)
//        	    volts[i] = lastVolts[i] + sign(volts[i]-lastVolts[i], limitStep);
            }
            int vn1 = pins[1].voltSource + sim.nodeList.size();
            if (expr != null) {
        	// calculate output
        	exprState.values[8] = cur;  // I = current
        	exprState.t = sim.t;
        	double v0 = expr.eval(exprState);
        	double rs = v0;
        	pins[2].current = v0;
        	pins[3].current = -v0;

        	double dv = 1e-6;
        	exprState.values[8] = cur+dv;
        	double v = expr.eval(exprState);
        	exprState.values[8] = cur-dv;
        	double v2 = expr.eval(exprState);
        	double dx = (v-v2)/(dv*2);
        	if (Math.abs(dx) < 1e-6)
        	    dx = sign(dx, 1e-6);
        	sim.stampCCCS(nodes[3], nodes[2], pins[1].voltSource, dx);
        	// adjust right side
        	rs -= dx*cur;
        	//                	sim.console("ccedx " + cur + " " + dx + " " + rs);
        	sim.stampCurrentSource(nodes[3], nodes[2], rs);
            }

            lastCurrent = cur;
        }
	
	int getPostCount() { return 4; }
	int getVoltageSourceCount() { return 1; }
	int getDumpType() { return 215; }
	boolean getConnection(int n1, int n2) {
	    if (comparePair(0, 1, n1, n2))
		return true;
	    if (comparePair(2, 3, n1, n2))
		return true;
	    return false;
	}
        boolean hasCurrentOutput() { return true; }
	
        void setCurrent(int vn, double c) {
            if (pins[1].voltSource == vn) {
        	pins[0].current = -c;
        	pins[1].current = c;
            }
        }
    }