//----------------------------------------------------------------------
// Includes
//----------------------------------------------------------------------
#include <iostream>
#include <cmath>
#include <stdexcept>

#include "MantidAPI/LogarithmScale.h"
#include "MantidAPI/TransformScaleFactory.h"
#include "MantidKernel/Logger.h"

namespace Mantid
{
namespace API
{
  namespace
  {
    /// static logger
    Kernel::Logger g_log("LogarithmScale");
  }


DECLARE_TRANSFORMSCALE(LogarithmScale);

void LogarithmScale::setBase( double &base)
{
  if( base <=0 )
  {
    g_log.error("Error: logarithm base must be a positive number");
  }
  m_base = base;
}

/* Transform the grid to adopt a logarithm scale.
 * @param gd a grid object
 */
void LogarithmScale::transform( std::vector<double> &gd )
{
  double a = 1.0/log(m_base);
  size_t n = gd.size();
  if(n==0) return; //no need to process
  if( gd.front() <=0 )
  {
    g_log.error("LogarithmScale::transform Error: negative values");
    return;
  }
  if(n<3) return; //no need to process
  double startX = a * log( gd.front() );
  double endX = a * log( gd.back() );
  double spacing = (endX-startX)/double(n);

  double x = startX + spacing;
  for(auto it=gd.begin()+1; it!=gd.end()-1; it++)
  {
    *it = pow(m_base,x);
    x += spacing;
  }
}



} // namespace API
} // namespace Mantid