Examples of ptolemy.math.Quantization

• ptolemy.math.Quantization
  The Quantization class defines the mapping of numeric values with unlimited precision to finite precision.

  It comprises a

  • precision: to define the accuracy of the finite precision numbers.
  • Overflow: to define the treatment of out-of-range numbers.
  • Rounding: to define the loss of precision for in-range numbers.

  The way in which precision is realised is a sub-class responsibility. The standard fixed point binary functionality using a Precision is provided by FixPointQuantization.

  This abstract class is designed to support specification of required numeric behavior through use of the yet-to-be-written FloatingQuantization and FixedQuantization classes. Knowledge of the required numeric behavior, rather than precise specification of an exact implementation, provides an opportunity for code generation to select appropriate types supported by a target architecture.

  FixedQuantization provides for modulo equi-spaced values between the inclusive maximum and minimum limits. epsilon, the separation between values is given by (maximum - minimum) / (modulo - 1). Whether values beyond the maximum and minimum wrap-around is determined by the overflow strategy. FixedQuantization therefore describes the requirements of a single fixed point range comprising just a mantissa.

  FloatingQuantization adds an exponent to support multiple floating point ranges; maximum defines the upper limit of the coarsest scale and tiny defines the smallest representable non-zero number on the finest scale. (tiny is the same as epsilon for FixedQuantization.)

  If exactRounding is specified, code generation must ensure that arithmetic rounds to the specified epsilon. Otherwise, the code generator may use arithmetic with higher precision.

  If exactOverflow is specified, code generation must ensure that arithmetic overflows saturate or wrap-around at the specified maximum and minimum. Otherwise, the code generator may use arithmetic with greater range.

  The active class functionality is provided by the quantize method, which is normally invoked from FixPoint.quantize or ScalarToken.quantize to enforce quantization constraints upon the result of an unconstrained computation.

  An instance of the class is immutable, meaning that its value is set in the constructor and cannot then be modified. @author Ed Willink @version $Id: Quantization.java,v 1.24 2007/12/07 06:30:28 cxh Exp $ @since Ptolemy II 2.1 @Pt.ProposedRating Red (Ed.Willink) @Pt.AcceptedRating Red @see ptolemy.math.FixPoint @see ptolemy.math.FixPointQuantization @see ptolemy.math.Precision @see ptolemy.math.Overflow @see ptolemy.math.Rounding

Related Classes of ptolemy.math.Quantization