tesseract  4.1.1
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 DPPointbest_prev () const
 
void AddLocalCost (int new_cost)
 

Static Public Member Functions

static DPPointSolve (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.

52  : local_cost_(0),
53  total_cost_(INT32_MAX),
54  total_steps_(1),
55  best_prev_(nullptr),
56  n_(0),
57  sig_x_(0),
58  sig_xsq_(0) {}

Member Function Documentation

◆ AddLocalCost()

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

Definition at line 81 of file dppoint.h.

81  {
82  local_cost_ += new_cost;
83  }

◆ best_prev()

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

Definition at line 78 of file dppoint.h.

78  {
79  return best_prev_;
80  }

◆ CostWithVariance()

int64_t tesseract::DPPoint::CostWithVariance ( const DPPoint prev)

Definition at line 69 of file dppoint.cpp.

69  {
70  if (prev == nullptr || prev == this) {
71  UpdateIfBetter(0, 1, nullptr, 0, 0, 0);
72  return 0;
73  }
74 
75  int delta = this - prev;
76  int32_t n = prev->n_ + 1;
77  int32_t sig_x = prev->sig_x_ + delta;
78  int64_t sig_xsq = prev->sig_xsq_ + delta * delta;
79  int64_t cost = (sig_xsq - sig_x * sig_x / n) / n;
80  cost += prev->total_cost_;
81  UpdateIfBetter(cost, prev->total_steps_ + 1, prev, n, sig_x, sig_xsq);
82  return cost;
83 }

◆ Pathlength()

int tesseract::DPPoint::Pathlength ( ) const
inline

Definition at line 75 of file dppoint.h.

75  {
76  return total_steps_;
77  }

◆ 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.

32  {
33  if (size <= 0 || max_step < min_step || min_step >= size)
34  return nullptr; // Degenerate, but not necessarily an error.
35  ASSERT_HOST(min_step > 0); // Infinite loop possible if this is not true.
36  if (debug)
37  tprintf("min = %d, max=%d\n",
38  min_step, max_step);
39  // Evaluate the total cost at each point.
40  for (int i = 0; i < size; ++i) {
41  for (int offset = min_step; offset <= max_step; ++offset) {
42  DPPoint* prev = offset <= i ? points + i - offset : nullptr;
43  int64_t new_cost = (points[i].*cost_func)(prev);
44  if (points[i].best_prev_ != nullptr && offset > min_step * 2 &&
45  new_cost > points[i].total_cost_)
46  break; // Find only the first minimum if going over twice the min.
47  }
48  points[i].total_cost_ += points[i].local_cost_;
49  if (debug) {
50  tprintf("At point %d, local cost=%d, total_cost=%d, steps=%d\n",
51  i, points[i].local_cost_, points[i].total_cost_,
52  points[i].total_steps_);
53  }
54  }
55  // Now find the end of the best path and return it.
56  int best_cost = points[size - 1].total_cost_;
57  int best_end = size - 1;
58  for (int end = best_end - 1; end >= size - min_step; --end) {
59  int cost = points[end].total_cost_;
60  if (cost < best_cost) {
61  best_cost = cost;
62  best_end = end;
63  }
64  }
65  return points + best_end;
66 }
#define ASSERT_HOST(x)
Definition: errcode.h:88
DLLSYM void tprintf(const char *format,...)
Definition: tprintf.cpp:35

◆ total_cost()

int tesseract::DPPoint::total_cost ( ) const
inline

Definition at line 72 of file dppoint.h.

72  {
73  return total_cost_;
74  }

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