Package cern.colt.matrix.impl

Class BenchmarkMatrix2D

  • class BenchmarkMatrix2D
extends java.lang.Object
    Benchmarks the performance of matrices. Here are the results of some encouraging measurements. Note that all benchmarks only measure the time spent in accessing a matrix element; they exclude the loop itself.

    Iteration Performance [million method calls per second]
    Pentium Pro 200 Mhz, SunJDK 1.2.2, NT, java -classic,
    60 times repeating the same iteration
    Element type
    		 Matrix2D type
    .

    DenseDoubleMatrix2D
    1000 x 1000

    		 

    SparseDoubleMatrix2D
    100 x 1000,
    minLoadFactor=0.2, maxLoadFactor=0.5, initialCapacity = 0
    getQuick setQuick     getQuick setQuick
    double 5 5     1 0.27
    int 5 5.5     1 0.3

    As can be seen, sparse matrices are certainly not quite as quick as dense ones, but not really slow either. Considering their minimal footprint they can be a real alternative.

    Comparing the OO abstractions to zero-abstraction primitive Java arrays may or may not be useful. Still, the table below provides some interesting information. For example, access to Type_T_Matrix2D is quicker than naive usage of Type_T_[]. Primitive arrays should only be considered if the optimized form can be applied. Note again that all benchmarks only measure the time spent in accessing a matrix element; they exclude the loop itself.

    Iteration Performance [million element accesses per second]
    Pentium Pro 200 Mhz, SunJDK 1.2.2, NT, java -classic,
    200 times repeating the same iteration
    Element type
    Matrix2D type = Java array double[][]
    .

    Unoptimized Form
    1000 x 1000

    for (int row=0; row < rows; row++) { 
   for (int col=0; col < columns; ) { 
          value = m[row][col++];
          ...
   }
}
    		Optimized Form
    1000 x 1000 
    for (int row=0; row < rows; row++) { 
   int[] r = matrix[row]; 
   for (int col=0; col < columns; ) { 
          value = r[col++];
          ...
   }
}
    getting setting getting setting
    double 1.6 1.8 18 11
    int 1.5 1.8 28 26
    Version:
    1.0, 09/24/99

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected BenchmarkMatrix2D()
      Makes this class non instantiable, but still let's others inherit from it.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static void doubleBenchmark​(int runs, int rows, int columns, java.lang.String kind, boolean print, int initialCapacity, double minLoadFactor, double maxLoadFactor)
      Runs a bench on matrices holding double elements.
      static void doubleBenchmarkMult​(int runs, int rows, int columns, java.lang.String kind, boolean print, int initialCapacity, double minLoadFactor, double maxLoadFactor)
      Runs a bench on matrices holding double elements.
      static void doubleBenchmarkPrimitive​(int runs, int rows, int columns, boolean print)
      Runs a bench on matrices holding double elements.
      static void doubleBenchmarkPrimitiveOptimized​(int runs, int rows, int columns, boolean print)
      Runs a bench on matrices holding double elements.
      static void intBenchmark​(int runs, int rows, int columns, java.lang.String kind, boolean print, int initialCapacity, double minLoadFactor, double maxLoadFactor)
      Runs a bench on matrices holding int elements.
      static void intBenchmarkPrimitive​(int runs, int rows, int columns, boolean print)
      Runs a bench on matrices holding int elements.
      static void intBenchmarkPrimitiveOptimized​(int runs, int rows, int columns, boolean print)
      Runs a bench on matrices holding int elements.
      static void main​(java.lang.String[] args)
      Benchmarks various methods of this class.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • BenchmarkMatrix2D

        protected BenchmarkMatrix2D()
        Makes this class non instantiable, but still let's others inherit from it.

    • Method Detail

      • doubleBenchmark

        public static void doubleBenchmark​(int runs,
                                   int rows,
                                   int columns,
                                   java.lang.String kind,
                                   boolean print,
                                   int initialCapacity,
                                   double minLoadFactor,
                                   double maxLoadFactor)
        Runs a bench on matrices holding double elements.

      • doubleBenchmarkMult

        public static void doubleBenchmarkMult​(int runs,
                                       int rows,
                                       int columns,
                                       java.lang.String kind,
                                       boolean print,
                                       int initialCapacity,
                                       double minLoadFactor,
                                       double maxLoadFactor)
        Runs a bench on matrices holding double elements.

      • doubleBenchmarkPrimitive

        public static void doubleBenchmarkPrimitive​(int runs,
                                            int rows,
                                            int columns,
                                            boolean print)
        Runs a bench on matrices holding double elements.

      • doubleBenchmarkPrimitiveOptimized

        public static void doubleBenchmarkPrimitiveOptimized​(int runs,
                                                     int rows,
                                                     int columns,
                                                     boolean print)
        Runs a bench on matrices holding double elements.

      • intBenchmark

        public static void intBenchmark​(int runs,
                                int rows,
                                int columns,
                                java.lang.String kind,
                                boolean print,
                                int initialCapacity,
                                double minLoadFactor,
                                double maxLoadFactor)
        Runs a bench on matrices holding int elements.

      • intBenchmarkPrimitive

        public static void intBenchmarkPrimitive​(int runs,
                                         int rows,
                                         int columns,
                                         boolean print)
        Runs a bench on matrices holding int elements.

      • intBenchmarkPrimitiveOptimized

        public static void intBenchmarkPrimitiveOptimized​(int runs,
                                                  int rows,
                                                  int columns,
                                                  boolean print)
        Runs a bench on matrices holding int elements.

      • main

        public static void main​(java.lang.String[] args)
        Benchmarks various methods of this class.