cosmotool/src/interpolate.cpp

#include <cassert>
#include <cmath>
#include <algorithm>
#include "interpolate.hpp"
#include <vector>
#include <fstream>
#include <inttypes.h>
#include <sstream>

using namespace std;
using namespace CosmoTool;
  
Interpolate::Interpolate(double *xs, double *values, uint32_t N, bool autofree,
			 bool logx, bool logy)
{
  spline = gsl_spline_alloc (gsl_interp_linear, N);
  gsl_spline_init (spline, xs, values, N);
  accel_interp = gsl_interp_accel_alloc();

  this->logx = logx;
  this->logy = logy;
  this->autoFree = autofree;
}

Interpolate::~Interpolate()
{
  if (spline != 0)
    gsl_spline_free (spline);
  if (accel_interp != 0)
    gsl_interp_accel_free (accel_interp);
}

double Interpolate::compute(double x)
  throw (InvalidRangeException)
{
  double y;
  
  if (logx)
    x = log(x);

  int err = gsl_spline_eval_e(spline, x, accel_interp, &y);

  if (err)
    throw InvalidRangeException("Interpolate argument outside range");

  if (logy)
    return exp(y);
  else
    return y;
}

double Interpolate::compute(double x) const
  throw (InvalidRangeException)
{
  double y;

  if (logx)
    x = log(x);

  int err = gsl_spline_eval_e(spline, x, 0, &y);

  if (err)
    throw InvalidRangeException("Interpolate argument outside range");

  if (logy)
    return exp(y);
  else
    return y;
}




double Interpolate::derivative(double x)
  throw (InvalidRangeException)
{
  double y, dy, x0 = x;
  
  if (logx)
    x0 = log(x0);

  int err = gsl_spline_eval_deriv_e(spline, x0, accel_interp, &dy);

  if (err)
    throw InvalidRangeException("Interpolate argument outside range");

  if (logy)
    {
      int err = gsl_spline_eval_e(spline, x0, accel_interp, &y);
      
      assert(err == 0);
      
      return dy*exp(y)/x0;
    }
  else
    return dy;
}

uint32_t Interpolate::getNumPoints() const
{
  return spline->size;
}

void Interpolate::fillWithXY(double *x, double *y) const
{
  if (x != 0)
    memcpy(x, spline->x, sizeof(double)*spline->size);
  if (y != 0)
    memcpy(y, spline->y, sizeof(double)*spline->size);
}

const Interpolate& Interpolate::operator=(const Interpolate& a)
{
  double *x, *y;

  if (spline != NULL)
    {
      gsl_spline_free (spline);
      gsl_interp_accel_free (accel_interp);
    }

  autoFree = true;
  spline = gsl_spline_alloc (gsl_interp_linear, a.spline->size);
  accel_interp = gsl_interp_accel_alloc ();
  gsl_spline_init(spline, a.spline->x, a.spline->y, a.spline->size);
  logx = a.logx;
  logy = a.logy;
}

double Interpolate::getMaxX() const
{
  if (logx)
    return exp(spline->x[spline->size-1]);
  else
    return spline->x[spline->size-1];
}

typedef struct {
  double a, b;
} MyPair;

bool operator<(const MyPair& a, const MyPair& b)
{
  return a.a < b.a;
}

Interpolate CosmoTool::buildFromVector(const InterpolatePairs& v)
{
  double *x = new double[v.size()];
  double *y = new double[v.size()];
  
  for (uint32_t i = 0; i < v.size(); i++)
    {
      x[i] = v[i].first;
      y[i] = v[i].second;
    }

  Interpolate inter = Interpolate(x, y, v.size(), true);

  delete[] x;
  delete[] y;

  return inter;  
}

Interpolate CosmoTool::buildInterpolateFromFile(const char *fname)
  throw (NoSuchFileException)
{
  vector<MyPair> allData;
  ifstream f(fname);

  if (!f)
    throw NoSuchFileException(fname);

  do 
    {
      MyPair m;

      if (!(f >> m.a >> m.b))
	break;

      allData.push_back(m);
    }
  while (1);

  sort(allData.begin(), allData.end());

  double *x = new double[allData.size()];
  double *y = new double[allData.size()];
  
  for (uint32_t i = 0; i < allData.size(); i++)
    {
      x[i] = allData[i].a;
      y[i] = allData[i].b;
    }

  Interpolate inter = Interpolate(x, y, allData.size(), true);

  delete[] x;
  delete[] y;

  return inter;
}

Interpolate CosmoTool::buildInterpolateFromColumns(const char *fname, uint32_t col1, uint32_t col2, bool logx,
						   bool logy)
  throw (NoSuchFileException,InvalidRangeException)
{
  vector<MyPair> allData;
  ifstream f(fname);

  if (!f)
    throw NoSuchFileException(fname);
  
  bool swapped = (col1 > col2);
  uint32_t colMin = min(col1, col2);
  uint32_t colMax = max(col1, col2);

  do 
    {
      MyPair m;
      string line;

      if (getline(f, line).eof())
	break;

      istringstream iss(line);
      double dummy;
      double val1, val2;

      for (uint32_t i = 0; i < colMin; i++)
	iss >> dummy;
      if (!(iss >> val1))
	throw InvalidRangeException("Invalid first column");

      if (col2 != col1)
	{
	  for (uint32_t i = 0; i < (colMax-colMin-1); i++)
	    iss >> dummy;
	  if (!(iss >> val2))
	    throw InvalidRangeException("Invalid second column");
	}
      else
	val2 = val2;

      if (!swapped)
	{
	  m.a = val1;
	  m.b = val2;
	}
      else
	{
	  m.a = val2;
	  m.b = val1;
	}

      allData.push_back(m);
    }
  while (1);

  sort(allData.begin(), allData.end());

  double *x = new double[allData.size()];
  double *y = new double[allData.size()];
  
  for (uint32_t i = 0; i < allData.size(); i++)
    {
      x[i] = logx ? log(allData[i].a) : allData[i].a;
      y[i] = logy ? log(allData[i].b) : allData[i].b;
    }

  Interpolate inter = Interpolate(x, y, allData.size(), true, logx, logy);

  delete[] x;
  delete[] y;
  
  return inter;
}