testBits.cpp File Reference

#include <cstdio>
#include <cmath>
#include <iostream>
#include "DGtal/base/Common.h"
#include "DGtal/base/Bits.h"

Include dependency graph for testBits.cpp:

Go to the source code of this file.

Functions
unsigned int	index (DGtal::uint32_t n, unsigned int b)
int	main ()

Detailed Description

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program 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 this program. If not, see http://www.gnu.org/licenses/.

Author

Jacques-Olivier Lachaud (jacqu.nosp@m.es-o.nosp@m.livie.nosp@m.r.la.nosp@m.chaud.nosp@m.@uni.nosp@m.v-sav.nosp@m.oie..nosp@m.fr ) Laboratory of Mathematics (CNRS, UMR 5807), University of Savoie, France

Date

2012/07/02

This file is part of the DGtal library

Definition in file testBits.cpp.

Function Documentation

index()

unsigned int index	(	DGtal::uint32_t	n,
		unsigned int	b
	)

Examples

examples/tutorial-examples/polyhedralizer.cpp, and tutorial-examples/polyhedralizer.cpp.

Definition at line 44 of file testBits.cpp.

{
  int i = 0;
  for ( ; b != 0; --b )
    {
      if ( n & 1 ) ++i;
      n >>= 1;
    }
  return ( n & 1 ) ? i + 1 : 0; 
}

Referenced by DGtal::ATSolver2D< TKSpace, TLinearAlgebra >::ATSolver2D(), main(), and testITKMethod().

main()

int main

(

void

)

Definition at line 56 of file testBits.cpp.

{
  unsigned int nb = 0;
  unsigned int nbok = 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint8_t)-1) == 8 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint16_t)-1) == 16 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint32_t)-1) == 32 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint64_t)-1) == 64 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint8_t)1) == 1 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint16_t)1) == 1 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint32_t)1) == 1 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint64_t)1) == 1 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint8_t)-2) == 7 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint16_t)-2) == 15 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint32_t)-2) == 31 ? 1 : 0;
  ++nb; nbok += Bits::nbSetBits( (DGtal::uint64_t)-2) == 63 ? 1 : 0;
 
  for ( unsigned int i = 0; i < 100; ++i )
    {
      DGtal::uint16_t n = (DGtal::uint16_t) ( rand() % 65536 ); 
      for ( unsigned int b = 0; b < 16; ++b )
      {
        ++nb; nbok += Bits::indexInSetBits( n, b ) == index( n, b ) ? 1 : 0;
      }
    }
 
  std::cerr << "(" << nbok << "/" << nb << ")" << " tests." << std::endl;
 
  trace.beginBlock ( "Testing speed of loop version of indexInSetBits" );
  srand( 0 );
  unsigned int val = 0;
  for ( unsigned int i = 0; i < 100000; ++i )
    {
      DGtal::uint32_t n = (DGtal::uint32_t) rand();
      for ( unsigned int b = 0; b < 32; ++b )
        val += index( n, b );
    }
  trace.info() << "- checksum = " << val << std::endl;
  trace.endBlock();
 
  trace.beginBlock ( "Testing speed of look-up table version of indexInSetBits" );
  srand( 0 );
  unsigned int val2 = 0;
  for ( unsigned int i = 0; i < 100000; ++i )
    {
      DGtal::uint32_t n = (DGtal::uint32_t) rand();
      for ( unsigned int b = 0; b < 32; ++b )
        val2 += Bits::indexInSetBits( n, b );
    }
  trace.info() << "- checksum = " << val2 << std::endl;
  trace.endBlock();
  ++nb; nbok += val == val2 ? 1 : 0;
  return ( nb == nbok ) ? 0 : 1;
}

References DGtal::Trace::beginBlock(), DGtal::Trace::endBlock(), index(), DGtal::Bits::indexInSetBits(), DGtal::Trace::info(), DGtal::Bits::nbSetBits(), srand(), and DGtal::trace.