source: tests/concurrency/examples/quickSort.generic.cfa @ ea10f64

//
// Cforall Version 1.0.0 Copyright (C) 2017 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// quickSort.c -- In-place concurrent quick-sort: threads are created to partition to a specific depth, then sequential
//              recursive-calls are use to sort each partition.
//
// Author           : Peter A. Buhr
// Created On       : Wed Dec  6 12:15:52 2017
// Last Modified By : Peter A. Buhr
// Last Modified On : Fri Jun 21 08:28:20 2019
// Update Count     : 149
//

#include <fstream.hfa>
#include <stdlib.hfa>
#include <kernel.hfa>
#include <thread.hfa>
#include <string.h>                                                                             // strcmp

forall( T | { int ?<?( T, T ); } ) {
        thread Quicksort {
                T * values;                                                                             // communication variables
                int low, high, depth;
        };

        void ?{}( Quicksort(T) & qs, T values[], int size, int depth ) {
                qs.values = values;  qs.low = 0;  qs.high = size;  qs.depth = depth;
        } // Quicksort

        void main( Quicksort(T) & qs ) {                                        // thread starts here
                // nested routines: information hiding

                void ?{}( Quicksort(T) & qs, T values[], int low, int high, int depth ) {
                        qs.values = values;  qs.low = low;  qs.high = high;  qs.depth = depth;
                } // Quicksort

                void sort( T values[], int low, int high, int depth ) {
                        int left, right;                                                        // index to left/right-hand side of the values
                        T pivot;                                                                        // pivot value of values
                        T swap;                                                                         // temporary

                        //verify();                                                                     // check for stack overflow due to recursion

                        // partition while 2 or more elements in the array
                        if ( low < high ) {
                                pivot = values[low + ( high - low ) / 2];
                                left  = low;
                                right = high;

                                // partition: move values less < pivot before the pivot and values > pivot after the pivot
                                do {
                                        while ( values[left] < pivot ) left += 1; // changed values[left] < pivot
                                        while ( pivot < values[right] ) right -= 1;
                                        if ( left <= right ) {
                                                swap = values[left];                    // interchange values
                                                values[left]  = values[right];
                                                values[right] = swap;
                                                left += 1;
                                                right -= 1;
                                        } // if
                                } while ( left <= right );

                                // restrict number of tasks to slightly greater than number of processors
                                if ( depth > 0 ) {
                                        depth -= 1;
                                        Quicksort(T) rqs = { values, low, right, depth }; // concurrently sort upper half
                                        //Quicksort lqs( values, left, high, depth ); // concurrently sort lower half
                                        sort( values, left, high, depth );      // concurrently sort lower half
                                } else {
                                        sort( values, low, right, 0 );          // sequentially sort lower half
                                        sort( values, left, high, 0 );          // sequentially sort upper half
                                } // if
                        } // if
                } // sort

                with( qs ) {
                        sort( values, low, high, depth );
                } // with
        } // main
}

bool convert( int & val, const char * nptr ) {                  // convert C string to integer
        char * eptr;
        int temp = strto( nptr, &eptr, 10 );                            // do not change val on false
        // true => entire string valid with no extra characters
        return *nptr != '\0' && *eptr == '\0' ? val = temp, true : false;
} // convert

void usage( char * argv[] ) {
        sout | "Usage:" | argv[0] | "( -s unsorted-file [ sorted-file ] | -t size (>= 0) [ depth (>= 0) ] )";
        exit( EXIT_FAILURE );                                                           // TERMINATE!
} // usage


#define ELEMTYPE int

int main( int argc, char * argv[] ) {
        ifstream & unsortedfile = sin;
        ofstream & sortedfile = sout;                                           // default value
        int depth = 0, size;

        if ( argc != 1 ) {                                                                      // do not use defaults
                if ( argc < 2 || argc > 4 ) usage( argv );              // wrong number of options
                if ( strcmp( argv[1], "-t" ) == 0 ) {                   // timing ?
                        &unsortedfile = (ifstream *)0;                          // no input
                        choose ( argc ) {
                          case 4:
                                if ( ! convert( depth, argv[3] ) || depth < 0 ) usage( argv );
                                fallthrough;
                          case 3:
                                if ( ! convert( size, argv[2] ) || size < 0 ) usage( argv );
                        } // choose
                } else {                                                                                // sort file
                        choose ( argc ) {
                          case 3:
                                &sortedfile = new( (const char *)argv[2] ); // open the output file
                                if ( fail( sortedfile ) ) {
                                        serr | "Error! Could not open sorted output file \"" | argv[2] | "\"";
                                        usage( argv );
                                } // if
                                fallthrough;
                          case 2:
                                &unsortedfile = new( (const char *)argv[1] ); // open the input file
                                if ( fail( unsortedfile ) ) {
                                        serr | "Error! Could not open unsorted input file \"" | argv[1] | "\"";
                                        usage( argv );
                                } // if
                        } // choose
                } // if
        } // if
        sortedfile | nlOff;                                                                     // turn off auto newline

        enum { ValuesPerLine = 22 };                                            // number of values printed per line

        if ( &unsortedfile ) {                                                          // generate output ?
                for () {
                        unsortedfile | size;                                            // read number of elements in the list
                  if ( eof( unsortedfile ) ) break;
                        ELEMTYPE * values = alloc( size );                      // values to be sorted, too large to put on stack
                        for ( counter; size ) {                                         // read unsorted numbers
                                unsortedfile | values[counter];
                                if ( counter != 0 && counter % ValuesPerLine == 0 ) sortedfile | nl | "  ";
                                sortedfile | values[counter];
                                if ( counter < size - 1 && (counter + 1) % ValuesPerLine != 0 ) sortedfile | ' ';
                        } // for
                        sortedfile | nl;
                        if ( size > 0 ) {                                                       // values to sort ?
                                Quicksort(ELEMTYPE) QS = { values, size - 1, 0 }; // sort values
                        } // wait until sort tasks terminate
                        for ( counter; size ) {                                         // print sorted list
                                if ( counter != 0 && counter % ValuesPerLine == 0 ) sortedfile | nl | "  ";
                                sortedfile | values[counter];
                                if ( counter < size - 1 && (counter + 1) % ValuesPerLine != 0 ) sortedfile | ' ';
                        } // for
                        sortedfile | nl | nl;

                        delete( values );
                } // for
                if ( &unsortedfile != &sin ) delete( &unsortedfile ); // close input/output files
                if ( &sortedfile != &sout ) delete( &sortedfile );
        } else {
                processor processors[ (1 << depth) - 1 ] __attribute__(( unused )); // create 2^depth-1 kernel threads

                ELEMTYPE * values = alloc( size );                              // values to be sorted, too large to put on stack
                for ( counter; size ) {                                                 // generate unsorted numbers
                        values[counter] = size - counter;                       // descending values
                } // for
                {
                        Quicksort(ELEMTYPE) QS = { values, size - 1, depth }; // sort values
                } // wait until sort tasks terminate

                // for ( counter; size - 1 ) {                                  // check sorting
                //      if ( values[counter] > values[counter + 1] ) abort();
                // } // for

                delete( values );
        } // if
} // main

// Local Variables: //
// tab-width: 4 //
// compile-command: "cfa quickSort.generic.cfa" //
// End: //