Package net.bmahe.genetics4j.core.chromosomes

Class FloatChromosome

java.lang.Object
net.bmahe.genetics4j.core.chromosomes.FloatChromosome
All Implemented Interfaces:
Chromosome
public class FloatChromosome extends Object implements Chromosome
A chromosome implementation that represents genetic information as an array of single-precision floating-point values.

FloatChromosome provides a memory-efficient alternative to DoubleChromosome for continuous optimization problems where single precision (32-bit) is sufficient. This chromosome type offers good performance for real-valued optimization while using approximately half the memory of double-precision alternatives.

This chromosome type is particularly suitable for:

  • Large-scale optimization: Problems with thousands of parameters where memory efficiency matters
  • Neural network evolution: Evolving weights when single precision is adequate
  • Graphics and gaming: Position, rotation, and scaling parameters
  • Signal processing: Audio and image processing parameter optimization
  • Embedded systems: Resource-constrained environments with limited memory
  • Real-time applications: Where performance is more critical than precision

Key characteristics:

  • Memory efficient: 32-bit floating-point representation reduces memory usage
  • Bounded values: All floats are constrained to [minValue, maxValue]
  • Fixed length: Chromosome size is determined at creation time
  • Immutable: Values cannot be changed after construction
  • IEEE 754 compliant: Standard floating-point arithmetic and comparisons

Performance considerations:

  • Memory usage: Approximately 50% less memory than DoubleChromosome
  • Cache efficiency: Better cache utilization due to smaller data size
  • Precision trade-off: ~7 decimal digits vs ~15 for double precision
  • Range limitations: Smaller representable range than double precision

The chromosome maintains bounds information which is used by genetic operators such as:

  • Arithmetic crossover: Weighted averaging of parent values
  • Gaussian mutation: Adding normally distributed noise
  • Uniform mutation: Random replacement within bounds
  • Creep mutation: Small incremental changes

When to choose FloatChromosome vs DoubleChromosome:

  • Use FloatChromosome: Large populations, memory constraints, adequate precision
  • Use DoubleChromosome: High precision requirements, scientific computing
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final float
    maxValue
     
    private final float
    minValue
     
    private final int
    size
     
    private final float[]
    values
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    FloatChromosome(int _size, float _minValue, float _maxValue, float[] _values)
    Creates a new float chromosome with the specified parameters and values.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    equals(Object obj)
     
    float
    getAllele(int index)
    Returns the float value at the specified index.
    float
    getMaxValue()
    Returns the maximum allowed value for floats in this chromosome.
    float
    getMinValue()
    Returns the minimum allowed value for floats in this chromosome.
    int
    getNumAlleles()
    Returns the number of alleles (genetic units) in this chromosome.
    int
    getSize()
    Returns the number of float values in this chromosome.
    float[]
    getValues()
    Returns a copy of the float values in this chromosome.
    int
    hashCode()
     
    String
    toString()
     

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • size

      private final int size

    • minValue

      private final float minValue

    • maxValue

      private final float maxValue

    • values

      private final float[] values

  • Constructor Details

    • FloatChromosome

      public FloatChromosome(int _size, float _minValue, float _maxValue, float[] _values)
      Creates a new float chromosome with the specified parameters and values.
      Parameters:
      _size - the number of float values in this chromosome
      _minValue - the minimum allowed value for any float in this chromosome
      _maxValue - the maximum allowed value for any float in this chromosome
      _values - the array of float values for this chromosome
      Throws:
      IllegalArgumentException - if size is not positive, if minValue > maxValue, if values array is null, or if the array length doesn't match the specified size

  • Method Details

    • getNumAlleles

      public int getNumAlleles()
      Description copied from interface: Chromosome
      Returns the number of alleles (genetic units) in this chromosome.

      The interpretation of an allele depends on the specific chromosome type:

      • For bit chromosomes: the number of bits
      • For numeric chromosomes: the number of numeric values
      • For tree chromosomes: the number of nodes in the tree
      Specified by:
      getNumAlleles in interface Chromosome
      Returns:
      the number of alleles in this chromosome, always positive

    • getAllele

      public float getAllele(int index)
      Returns the float value at the specified index.
      Parameters:
      index - the index of the allele to retrieve (0-based)
      Returns:
      the float value at the specified position
      Throws:
      IllegalArgumentException - if index is negative or greater than or equal to the chromosome size

    • getSize

      public int getSize()
      Returns the number of float values in this chromosome.
      Returns:
      the chromosome size

    • getMinValue

      public float getMinValue()
      Returns the minimum allowed value for floats in this chromosome.
      Returns:
      the minimum value constraint

    • getMaxValue

      public float getMaxValue()
      Returns the maximum allowed value for floats in this chromosome.
      Returns:
      the maximum value constraint

    • getValues

      public float[] getValues()
      Returns a copy of the float values in this chromosome.

      The returned array is a defensive copy; modifications to it will not affect this chromosome.

      Returns:
      a copy of the float values array

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object