tesseract::DPPoint Class Reference

#include <dppoint.h>

Public Types
using	CostFunc = int64_t(DPPoint::*)(const DPPoint *)

Public Member Functions
	DPPoint ()
int64_t	CostWithVariance (const DPPoint *prev)
int	total_cost () const
int	Pathlength () const
const DPPoint *	best_prev () const
void	AddLocalCost (int new_cost)

Static Public Member Functions
static DPPoint *	Solve (int min_step, int max_step, bool debug, CostFunc cost_func, int size, DPPoint *points)

Detailed Description

Definition at line 44 of file dppoint.h.

Member Typedef Documentation

CostFunc

using tesseract::DPPoint::CostFunc = int64_t (DPPoint::*)(const DPPoint *)

Definition at line 49 of file dppoint.h.

Constructor & Destructor Documentation

DPPoint()

tesseract::DPPoint::DPPoint ( )

inline

Definition at line 51 of file dppoint.h.

      : local_cost_(0)
      , total_cost_(INT32_MAX)
      , total_steps_(1)
      , best_prev_(nullptr)
      , n_(0)
      , sig_x_(0)
      , sig_xsq_(0) {}

Member Function Documentation

AddLocalCost()

void tesseract::DPPoint::AddLocalCost ( int  new_cost )

inline

Definition at line 81 of file dppoint.h.

                                  {
    local_cost_ += new_cost;
  }

best_prev()

const DPPoint * tesseract::DPPoint::best_prev ( ) const

inline

Definition at line 78 of file dppoint.h.

                                   {
    return best_prev_;
  }

CostWithVariance()

int64_t tesseract::DPPoint::CostWithVariance

(

const DPPoint *

prev

)

Definition at line 70 of file dppoint.cpp.

                                                     {
  if (prev == nullptr || prev == this) {
    UpdateIfBetter(0, 1, nullptr, 0, 0, 0);
    return 0;
  }
 
  int delta = this - prev;
  int32_t n = prev->n_ + 1;
  int32_t sig_x = prev->sig_x_ + delta;
  int64_t sig_xsq = prev->sig_xsq_ + static_cast<int64_t>(delta) * delta;
  int64_t cost = (sig_xsq - sig_x * sig_x / n) / n;
  cost += prev->total_cost_;
  UpdateIfBetter(cost, prev->total_steps_ + 1, prev, n, sig_x, sig_xsq);
  return cost;
}

Pathlength()

int tesseract::DPPoint::Pathlength ( ) const

inline

Definition at line 75 of file dppoint.h.

                         {
    return total_steps_;
  }

Solve()

DPPoint * tesseract::DPPoint::Solve ( int  min_step, int  max_step, bool  debug, CostFunc  cost_func, int  size, DPPoint *  points  )

static

Definition at line 31 of file dppoint.cpp.

                                         {
  if (size <= 0 || max_step < min_step || min_step >= size) {
    return nullptr; // Degenerate, but not necessarily an error.
  }
  ASSERT_HOST(min_step > 0); // Infinite loop possible if this is not true.
  if (debug) {
    tprintf("min = %d, max=%d\n", min_step, max_step);
  }
  // Evaluate the total cost at each point.
  for (int i = 0; i < size; ++i) {
    for (int offset = min_step; offset <= max_step; ++offset) {
      DPPoint *prev = offset <= i ? points + i - offset : nullptr;
      int64_t new_cost = (points[i].*cost_func)(prev);
      if (points[i].best_prev_ != nullptr && offset > min_step * 2 &&
          new_cost > points[i].total_cost_) {
        break; // Find only the first minimum if going over twice the min.
      }
    }
    points[i].total_cost_ += points[i].local_cost_;
    if (debug) {
      tprintf("At point %d, local cost=%d, total_cost=%d, steps=%d\n", i, points[i].local_cost_,
              points[i].total_cost_, points[i].total_steps_);
    }
  }
  // Now find the end of the best path and return it.
  int best_cost = points[size - 1].total_cost_;
  int best_end = size - 1;
  for (int end = best_end - 1; end >= size - min_step; --end) {
    int cost = points[end].total_cost_;
    if (cost < best_cost) {
      best_cost = cost;
      best_end = end;
    }
  }
  return points + best_end;
}

total_cost()

int tesseract::DPPoint::total_cost ( ) const

inline

Definition at line 72 of file dppoint.h.

                         {
    return total_cost_;
  }

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The documentation for this class was generated from the following files:

• /media/home/debian/src/github/tesseract-ocr/tesseract/src/ccstruct/dppoint.h
• /media/home/debian/src/github/tesseract-ocr/tesseract/src/ccstruct/dppoint.cpp