Examples of ptolemy.math.FixPoint

ptolemy.math.FixPoint
The FixPoint class provides a fixed point data type and a set of functions that operate on and return fixed point data. An instance of the class is immutable, meaning that its value is set in the constructor and cannot then be modified. This is similar to the Java built-in classes like Double, Integer, etc.
The FixPoint class represents signed numbers in a two's-complement format or unsigned numbers in a binary format with unlimited dynamic range and a resolution defined by a finite number of fractional bits. The precision is defined by the {@link ptolemy.math.Precision Precision} class.
Because a fixed point data type uses a finite number of bits to represent a value, a real value is converted to a number that can be expressed with a given precision of the fixed point, thereby introducing a quantization error. The overflow and rounding strategies used for this quantization are defined by an instance of the {@link ptolemy.math.Quantization Quantization} class.
The design of the FixPoint class complies with a philosophy that all operators work losslessly, i.e. the fractional precision of the result is determined such there is no loss of precision. To insure lossless operations, the resulting Precision of these operators will expand as necessary. Subsequent results can be quantized as necessary.
Violations of the loss-less philosophy occur during construction, division and conversion to floating point. During construction from floating point values, the nearest fixed point representation is created. The preferred divide operator provides for explicit specification of the quantization. A deprecated divide operator guesses at the result precision. Conversion to floating point is limited by the available floating point accuracy.
The FixPoint implementation uses the Java class BigInteger to represent the finite value and so this implementation is truly platform independent. Note that the FixPoint does not put any restrictions on the maximum number of bits in the representation of a value. @author Bart Kienhuis, Ed Willink, Contributor: Edward A. Lee, Mike Wirthlin @version $Id: FixPoint.java,v 1.84 2007/12/07 06:30:32 cxh Exp $ @since Ptolemy II 0.4, rewritten for Ptolemy II 2.2 @Pt.ProposedRating Red (Ed.Willink) @Pt.AcceptedRating Red @see ptolemy.math.Precision @see ptolemy.math.Quantization

     *  that the type of the argument is an FixToken.
     *  @param rightArgument The token to add to this token.
     *  @return A new FixToken containing the result.
     */
    protected ScalarToken _add(ScalarToken rightArgument) {
        FixPoint result = _value.add(((FixToken) rightArgument).fixValue());
        return new FixToken(result);
    }

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     *  the type of the argument is an FixToken
     *  @param rightArgument The token to divide this token by.
     *  @return A new FixToken containing the result.
     */
    protected ScalarToken _divide(ScalarToken rightArgument) {
        FixPoint result = _value.divide(((FixToken) rightArgument).fixValue());
        return new FixToken(result);
    }

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     *  @param rightArgument The token to divide this token by.
     *  @param quant The quantization specification.
     *  @return A new FixToken containing the result.
     */
    protected ScalarToken _divide(ScalarToken rightArgument, Quantization quant) {
        FixPoint result = _value.divide(((FixToken) rightArgument).fixValue(),
                quant);
        return new FixToken(result);
    }

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     *  the type of the argument is an FixToken.
     *  @param rightArgument The token to multiply this token by.
     *  @return A new FixToken containing the result.
     */
    protected ScalarToken _multiply(ScalarToken rightArgument) {
        FixPoint result = _value
                .multiply(((FixToken) rightArgument).fixValue());
        return new FixToken(result);
    }

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     *  with a quantization specification.
     *  @param quant The quantization specification.
     *  @return A new FixToken containing the result.
     */
    protected FixToken _quantize(Quantization quant) {
        FixPoint result = _value.quantize(quant);
        return new FixToken(result);
    }

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     *  the type of the argument is an FixToken.
     *  @param rightArgument The token to subtract from this token.
     *  @return A new FixToken containing the result.
     */
    protected ScalarToken _subtract(ScalarToken rightArgument) {
        FixPoint result = _value
                .subtract(((FixToken) rightArgument).fixValue());
        return new FixToken(result);
    }

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    /** Return the value in the token as a fixpoint.
     *  @return The value contained in this token as a fixpoint.
     */
    public FixPoint fixValue() {
        // FIXME: Does FixPoint need to specially handle Short?
        return new FixPoint(_value);
    }

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                    localName, stringTokenClass, stringTokenConstructor,
                    StringConstant.v(((StringToken) token).stringValue()));
            return tokenLocal;
        } else if (token instanceof FixToken) {
            FixToken fixToken = (FixToken) token;
            FixPoint fixValue = fixToken.fixValue();
            List args = new ArrayList(3);


            // Some possible loss of precision?
            args.add(DoubleConstant.v(fixValue.doubleValue()));
            args.add(IntConstant.v(fixValue.getPrecision().getNumberOfBits()));
            args.add(IntConstant.v(fixValue.getPrecision()
                    .getIntegerBitLength()));


            Local tokenLocal = _buildConstantTokenLocal(body, insertPoint,
                    localName, fixTokenClass, fixTokenThreeArgConstructor, args);
            return tokenLocal;

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            if (!address.hasToken(0)) {
                return;
            }


            FixToken addressToken = (FixToken) address.get(0);
            FixPoint addressFixValue = addressToken.fixValue();


            _checkFixTokenWidth(addressToken, _addressWidth);


            addressValue = addressFixValue.getUnscaledValue().intValue();


            if (addressValue >= _capacity) {
                throw new IllegalActionException(this,
                        "Address is out of range.");
            }


            ArrayToken valuesArray = (ArrayToken) values.getToken();
            FixPoint value = new FixPoint(((ScalarToken) valuesArray
                    .getElement(addressValue)).intValue());
            Token result = new FixToken(value);
            if (result == null) {
                result = Token.NIL;
            }

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        }


        //FIXME: what do we do if input is negative?
        //bits = bits.replace('-', '1');


        FixPoint result = new FixPoint(new BigDecimal(new BigInteger(bits
                .toString(), 2)), new FixPointQuantization(precision, overflow,
                rounding));


        sendOutput(output, 0, new FixToken(result));
    }

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ptolemy.actor.lib.conversions.FixToFix

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ptolemy.actor.lib.vhdl.FixConst

ptolemy.actor.lib.vhdl.FixCounter

ptolemy.actor.lib.vhdl.FixSequence

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