/usr/lib/grass74/include/grass/iostream/minmaxheap.h is in grass-dev 7.4.0-1.
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*
* MODULE: iostream
*
* COPYRIGHT (C) 2007 Laura Toma
*
*
* Iostream is a library that implements streams, external memory
* sorting on streams, and an external memory priority queue on
* streams. These are the fundamental components used in external
* memory algorithms.
* Credits: The library was developed by Laura Toma. The kernel of
* class STREAM is based on the similar class existent in the GPL TPIE
* project developed at Duke University. The sorting and priority
* queue have been developed by Laura Toma based on communications
* with Rajiv Wickremesinghe. The library was developed as part of
* porting Terraflow to GRASS in 2001. PEARL upgrades in 2003 by
* Rajiv Wickremesinghe as part of the Terracost project.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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. *
* **************************************************************************/
#ifndef _MINMAXHEAP_H
#define _MINMAXHEAP_H
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <math.h>
#ifdef log2
#undef log2
#endif
#include <sstream>
#include "mm_utils.h"
#include "ami_config.h" //for SAVE_MEMORY flag
/* this flag is set if we are stingy on memory; in that case 'reset'
deletes the pq memory and the subsequent insert reallocates it; if
the operation following a reset is not an insert or an operation
which does not touch the array A, behaviour is unpredictable (core
dump probably) */
/*****************************************************************
*****************************************************************
*****************************************************************
Priority queue templated on a single type (assumed to be a class with
getPriority() and getValue() implemented);
Supported operations: min, extract_min, insert, max, extract_max in
O(lg n)
*****************************************************************
*****************************************************************
*****************************************************************/
#undef XXX
#define XXX if(0)
#define MY_LOG_DEBUG_ID(x) //inhibit debug printing
//#define MY_LOG_DEBUG_ID(x) LOG_DEBUG_ID(x)
typedef unsigned int HeapIndex;
template <class T>
class BasicMinMaxHeap {
protected:
HeapIndex maxsize;
HeapIndex lastindex; // last used position (0 unused) (?)
T *A;
protected:
/* couple of memory mgt functions to keep things consistent */
static T *allocateHeap(HeapIndex n);
static void freeHeap(T *);
public:
BasicMinMaxHeap(HeapIndex size) : maxsize(size) {
char str[100];
sprintf(str, "BasicMinMaxHeap: allocate %ld\n",
(long)((size+1)*sizeof(T)));
// MEMORY_LOG(str);
lastindex = 0;
MY_LOG_DEBUG_ID("minmaxheap: allocation");
A = allocateHeap(maxsize);
};
virtual ~BasicMinMaxHeap(void) {
MY_LOG_DEBUG_ID("minmaxheap: deallocation");
freeHeap(A);
};
bool empty(void) const { return size() == 0; };
HeapIndex size() const {
assert(A || !lastindex);
return lastindex;
};
T get(HeapIndex i) const { assert(i <= size()); return A[i]; }
//build a heap from an array of elements;
//if size > maxsize, insert first maxsize elements from array;
//return nb of elements that did not fit;
void insert(const T& elt);
bool min(T& elt) const ;
bool extract_min(T& elt);
bool max(T& elt) const;
bool extract_max(T& elt);
//extract all elts with min key, add them and return their sum
bool extract_all_min(T& elt);
void reset();
void clear(); /* mark all the data as deleted, but don't do free */
void destructiveVerify();
void verify();
void print() const;
void print_range() const;
friend ostream& operator<<(ostream& s, const BasicMinMaxHeap<T> &pq) {
HeapIndex i;
s << "[";
for(i = 1; i <= pq.size(); i++) {
s << " " << pq.get(i);
}
s << "]";
return s;
}
protected:
virtual void grow()=0;
private:
long log2(long n) const;
int isOnMaxLevel(HeapIndex i) const { return (log2(i) % 2); };
int isOnMinLevel(HeapIndex i) const { return !isOnMaxLevel(i); };
HeapIndex leftChild(HeapIndex i) const { return 2*i; };
HeapIndex rightChild(HeapIndex i) const { return 2*i + 1; };
int hasRightChild(HeapIndex i) const { return (rightChild(i) <= size()); };
int hasRightChild(HeapIndex i, HeapIndex *c) const { return ((*c=rightChild(i)) <= size()); };
HeapIndex parent(HeapIndex i) const { return (i/2); };
HeapIndex grandparent(HeapIndex i) const { return (i/4); };
int hasChildren(HeapIndex i) const { return (2*i) <= size(); }; // 1 or more
void swap(HeapIndex a, HeapIndex b);
T leftChildValue(HeapIndex i) const;
T rightChildValue(HeapIndex i) const;
HeapIndex smallestChild(HeapIndex i) const;
HeapIndex smallestChildGrandchild(HeapIndex i) const;
HeapIndex largestChild(HeapIndex i) const;
HeapIndex largestChildGrandchild(HeapIndex i) const;
int isGrandchildOf(HeapIndex i, HeapIndex m) const;
void trickleDownMin(HeapIndex i);
void trickleDownMax(HeapIndex i);
void trickleDown(HeapIndex i);
void bubbleUp(HeapIndex i);
void bubbleUpMin(HeapIndex i);
void bubbleUpMax(HeapIndex i);
};
// index 0 is invalid
// index <= size
// ----------------------------------------------------------------------
template <class T>
long BasicMinMaxHeap<T>::log2(long n) const {
long i=-1;
// let log2(0)==-1
while(n) {
n = n >> 1;
i++;
}
return i;
}
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::swap(HeapIndex a, HeapIndex b) {
T tmp;
tmp = A[a];
A[a] = A[b];
A[b] = tmp;
}
// ----------------------------------------------------------------------
// child must exist
template <class T>
T BasicMinMaxHeap<T>::leftChildValue(HeapIndex i) const {
HeapIndex p = leftChild(i);
assert(p <= size());
return A[p];
}
// ----------------------------------------------------------------------
// child must exist
template <class T>
T BasicMinMaxHeap<T>::rightChildValue(HeapIndex i) const {
HeapIndex p = rightChild(i);
assert(p <= size());
return A[p];
}
// ----------------------------------------------------------------------
// returns index of the smallest of children of node
// it is an error to call this function if node has no children
template <class T>
HeapIndex BasicMinMaxHeap<T>::smallestChild(HeapIndex i) const {
assert(hasChildren(i));
if(hasRightChild(i) && (leftChildValue(i) > rightChildValue(i))) {
return rightChild(i);
} else {
return leftChild(i);
}
}
// ----------------------------------------------------------------------
template <class T>
HeapIndex BasicMinMaxHeap<T>::largestChild(HeapIndex i) const {
assert(hasChildren(i));
if(hasRightChild(i) && (leftChildValue(i) < rightChildValue(i))) {
return rightChild(i);
} else {
return leftChild(i);
}
}
// ----------------------------------------------------------------------
// error to call on node without children
template <class T>
HeapIndex BasicMinMaxHeap<T>::smallestChildGrandchild(HeapIndex i) const {
HeapIndex p,q;
HeapIndex minpos = 0;
assert(hasChildren(i));
p = leftChild(i);
if(hasChildren(p)) {
q = smallestChild(p);
if(A[p] > A[q]) p = q;
}
// p is smallest of left child, its grandchildren
minpos = p;
if(hasRightChild(i,&p)) {
//p = rightChild(i);
if(hasChildren(p)) {
q = smallestChild(p);
if(A[p] > A[q]) p = q;
}
// p is smallest of right child, its grandchildren
if(A[p] < A[minpos]) minpos = p;
}
return minpos;
}
// ----------------------------------------------------------------------
template <class T>
HeapIndex BasicMinMaxHeap<T>::largestChildGrandchild(HeapIndex i) const {
HeapIndex p,q;
HeapIndex maxpos = 0;
assert(hasChildren(i));
p = leftChild(i);
if(hasChildren(p)) {
q = largestChild(p);
if(A[p] < A[q]) p = q;
}
// p is smallest of left child, its grandchildren
maxpos = p;
if(hasRightChild(i,&p)) {
//p = rightChild(i);
if(hasChildren(p)) {
q = largestChild(p);
if(A[p] < A[q]) p = q;
}
// p is smallest of right child, its grandchildren
if(A[p] > A[maxpos]) maxpos = p;
}
return maxpos;
}
// ----------------------------------------------------------------------
// this is pretty loose - only to differentiate between child and grandchild
template <class T>
int BasicMinMaxHeap<T>::isGrandchildOf(HeapIndex i, HeapIndex m) const {
return (m >= i*4);
}
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::trickleDownMin(HeapIndex i) {
HeapIndex m;
bool done = false;
while (!done) {
if (!hasChildren(i)) {
done = true;
return;
}
m = smallestChildGrandchild(i);
if(isGrandchildOf(i, m)) {
if(A[m] < A[i]) {
swap(i, m);
if(A[m] > A[parent(m)]) {
swap(m, parent(m));
}
//trickleDownMin(m);
i = m;
} else {
done = true;
}
} else {
if(A[m] < A[i]) {
swap(i, m);
}
done = true;
}
}//while
}
// ----------------------------------------------------------------------
// unverified
template <class T>
void BasicMinMaxHeap<T>::trickleDownMax(HeapIndex i) {
HeapIndex m;
bool done = false;
while (!done) {
if(!hasChildren(i)) {
done = true;
return;
}
m = largestChildGrandchild(i);
if(isGrandchildOf(i, m)) {
if(A[m] > A[i]) {
swap(i, m);
if(A[m] < A[parent(m)]) {
swap(m, parent(m));
}
//trickleDownMax(m);
i = m;
} else {
done = true;
}
} else {
if(A[m] > A[i]) {
swap(i, m);
}
done = true;
}
} //while
}
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::trickleDown(HeapIndex i) {
if(isOnMinLevel(i)) {
trickleDownMin(i);
} else {
trickleDownMax(i);
}
}
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::bubbleUp(HeapIndex i) {
HeapIndex m;
m = parent(i);
if(isOnMinLevel(i)) {
if (m && (A[i] > A[m])) {
swap(i, m);
bubbleUpMax(m);
} else {
bubbleUpMin(i);
}
} else {
if (m && (A[i] < A[m])) {
swap(i, m);
bubbleUpMin(m);
} else {
bubbleUpMax(i);
}
}
}
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::bubbleUpMin(HeapIndex i) {
HeapIndex m;
m = grandparent(i);
while (m && (A[i] < A[m])) {
swap(i,m);
//bubbleUpMin(m);
i = m;
m = grandparent(i);
}
}
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::bubbleUpMax(HeapIndex i) {
HeapIndex m;
m = grandparent(i);
while(m && (A[i] > A[m])) {
swap(i,m);
//bubbleUpMax(m);
i=m;
m = grandparent(i);
}
}
#if(0)
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::print_rajiv() const {
HeapIndex i;
ostrstream *ostr = new ostrstream();
*ostr << "[1]";
for(i=1; i<=size(); i++) {
*ostr << " " << A[i];
if(ostr->pcount() > 70) {
cout << ostr->str() << endl;
delete ostr;
ostr = new ostrstream();
*ostr << "[" << i << "]";
}
}
cout << ostr->str() << endl;
}
#endif
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::print() const {
cout << "[";
for (unsigned int i=1; i<=size(); i++) {
cout << A[i].getPriority() <<",";
}
cout << "]" << endl;
}
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::print_range() const {
cout << "[";
T a, b;
min(a);
max(b);
if (size()) {
cout << a.getPriority() << ".."
<< b.getPriority();
}
cout << " (" << size() << ")]";
}
// ----------------------------------------------------------------------
template <class T>
void BasicMinMaxHeap<T>::insert(const T& elt) {
#ifdef SAVE_MEMORY
if (!A) {
MY_LOG_DEBUG_ID("minmaxheap: re-allocation");
A = allocateHeap(maxsize);
}
#endif
if(lastindex == maxsize) grow();
XXX cerr << "insert: " << elt << endl;
lastindex++;
A[lastindex] = elt;
bubbleUp(lastindex);
}
// ----------------------------------------------------------------------
template <class T>
bool BasicMinMaxHeap<T>::extract_min(T& elt) {
assert(A);
if(lastindex == 0) return false;
elt = A[1];
A[1] = A[lastindex];
lastindex--;
trickleDown(1);
return true;
}
// ----------------------------------------------------------------------
//extract all elts with min key, add them and return their sum
template <class T>
bool BasicMinMaxHeap<T>::extract_all_min(T& elt) {
T next_elt;
bool done = false;
//extract first elt
if (!extract_min(elt)) {
return false;
} else {
while (!done) {
//peek at the next min elt to see if matches
if ((!min(next_elt)) ||
!(next_elt.getPriority() == elt.getPriority())) {
done = true;
} else {
extract_min(next_elt);
elt = elt + next_elt;
}
}
}
return true;
}
// ----------------------------------------------------------------------
template <class T>
bool BasicMinMaxHeap<T>::extract_max(T& elt) {
assert(A);
HeapIndex p; // max
if(lastindex == 0) return false;
if(hasChildren(1)) {
p = largestChild(1);
} else {
p = 1;
}
elt = A[p];
A[p] = A[lastindex];
lastindex--;
trickleDown(p);
return true;
}
// ----------------------------------------------------------------------
template <class T>
bool BasicMinMaxHeap<T>::min(T& elt) const {
assert(A);
if(lastindex == 0) return false;
elt = A[1];
return true;
}
// ----------------------------------------------------------------------
template <class T>
bool BasicMinMaxHeap<T>::max(T& elt) const {
assert(A);
HeapIndex p; // max
if(lastindex == 0) return false;
if(hasChildren(1)) {
p = largestChild(1);
} else {
p = 1;
}
elt = A[p];
return true;
}
// ----------------------------------------------------------------------
//free memory if SAVE_MEMORY is set
template <class T>
void BasicMinMaxHeap<T>::reset() {
#ifdef SAVE_MEMORY
assert(empty());
MY_LOG_DEBUG_ID("minmaxheap: deallocation");
freeHeap(A);
A = NULL;
#endif
}
// ----------------------------------------------------------------------
template <class T>
void
BasicMinMaxHeap<T>::clear() {
lastindex = 0;
}
// ----------------------------------------------------------------------
template <class T>
T *
BasicMinMaxHeap<T>::allocateHeap(HeapIndex n) {
T *p;
#ifdef USE_LARGEMEM
p = (T*)LargeMemory::alloc(sizeof(T) * (n+1));
#else
p = new T[n+1];
#endif
return p;
}
// ----------------------------------------------------------------------
template <class T>
void
BasicMinMaxHeap<T>::freeHeap(T *p) {
if (p) {
#ifdef USE_LARGEMEM
LargeMemory::free(p);
#else
delete [] p;
#endif
}
}
// ----------------------------------------------------------------------
template <class T>
void
BasicMinMaxHeap<T>::destructiveVerify() {
HeapIndex n = size();
T val, prev;
bool ok;
if(!n) return;
XXX print();
/* make sure that min works */
extract_min(prev);
for(HeapIndex i=1; i<n; i++) {
ok = min(val);
assert(ok);
XXX cerr << i << ": " << val << endl;
if(val.getPriority() < prev.getPriority()) { // oops!
print();
cerr << "n=" << n << endl;
cerr << "val=" << val << endl;
cerr << "prev=" << prev << endl;
cerr << "looks like minmaxheap.min is broken!!" << endl;
assert(0);
return;
}
prev = val;
ok = extract_min(val);
assert(ok);
assert(prev == val);
}
}
// ----------------------------------------------------------------------
template <class T>
void
BasicMinMaxHeap<T>::verify() {
long n = size();
T *dup;
if(!n) return;
dup = allocateHeap(maxsize);
for(HeapIndex i=0; i<n+1; i++) {
dup[i] = A[i];
}
destructiveVerify();
freeHeap(A);
/* restore the heap */
A = dup;
lastindex = n;
}
// ----------------------------------------------------------------------
// ----------------------------------------------------------------------
template <class T>
class MinMaxHeap : public BasicMinMaxHeap<T> {
public:
MinMaxHeap(HeapIndex size) : BasicMinMaxHeap<T>(size) {};
virtual ~MinMaxHeap() {};
bool full(void) const { return this->size() >= this->maxsize; };
HeapIndex get_maxsize() const { return this->maxsize; };
HeapIndex fill(T* arr, HeapIndex n);
protected:
virtual void grow() { fprintf(stderr, "MinMaxHeap::grow: not implemented\n"); assert(0); exit(1); };
};
// ----------------------------------------------------------------------
//build a heap from an array of elements;
//if size > maxsize, insert first maxsize elements from array;
//return nb of elements that did not fit;
template <class T>
HeapIndex MinMaxHeap<T>::fill(T* arr, HeapIndex n) {
HeapIndex i;
//heap must be empty
assert(this->size()==0);
for (i = 0; !full() && i<n; i++) {
this->insert(arr[i]);
}
if (i < n) {
assert(i == this->maxsize);
return n - i;
} else {
return 0;
}
}
#define MMHEAP_INITIAL_SIZE 1024
template <class T>
class UnboundedMinMaxHeap : public BasicMinMaxHeap<T> {
public:
UnboundedMinMaxHeap() : BasicMinMaxHeap<T>(MMHEAP_INITIAL_SIZE) {};
UnboundedMinMaxHeap(HeapIndex size) : BasicMinMaxHeap<T>(size) {};
virtual ~UnboundedMinMaxHeap() {};
protected:
virtual void grow();
};
template <class T>
void UnboundedMinMaxHeap<T>::grow() {
T *old = this->A;
this->maxsize *= 2;
assert(this->maxsize > 0);
if(old) {
HeapIndex n = this->size();
this->A = this->allocateHeap(this->maxsize); /* allocate a new array */
/* copy over the old values */
assert(this->maxsize > n);
for(HeapIndex i=0; i<=n; i++) { /* why extra value? -RW */
this->A[i] = old[i];
}
this->freeHeap(old); /* free up old storage */
}
}
#endif
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