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/* $Id: network.cpp 1662 2011-01-04 17:52:40Z lou $ */
// Copyright (C) 2002, International Business Machines
// Corporation and others. All Rights Reserved.
// This code is licensed under the terms of the Eclipse Public License (EPL).
// The point of this example is to show how to create a model without
// using mps files.
// This reads a network problem created by netgen which can be
// downloaded from www.netlib.org/lp/generators/netgen
// This is a generator due to Darwin Klingman
#include "ClpSimplex.hpp"
#include "ClpFactorization.hpp"
#include "ClpNetworkMatrix.hpp"
#include <stdio.h>
#include <assert.h>
#include <cmath>
int main(int argc, const char *argv[])
{
int numberColumns;
int numberRows;
FILE * fp;
if (argc > 1) {
fp = fopen(argv[1], "r");
if (!fp) {
fprintf(stderr, "Unable to open file %s\n", argv[1]);
exit(1);
}
} else {
fp = fopen("input.130", "r");
if (!fp) {
fprintf(stderr, "Unable to open file input.l30 in Samples directory\n");
exit(1);
}
}
int problem;
char temp[100];
// read and skip
fscanf(fp, "%s", temp);
assert(!strcmp(temp, "BEGIN"));
fscanf(fp, "%*s %*s %d %d %*s %*s %d %*s", &problem, &numberRows,
&numberColumns);
// scan down to SUPPLY
while (fgets(temp, 100, fp)) {
if (!strncmp(temp, "SUPPLY", 6))
break;
}
if (strncmp(temp, "SUPPLY", 6)) {
fprintf(stderr, "Unable to find SUPPLY\n");
exit(2);
}
// get space for rhs
double * lower = new double[numberRows];
double * upper = new double[numberRows];
int i;
for (i = 0; i < numberRows; i++) {
lower[i] = 0.0;
upper[i] = 0.0;
}
// ***** Remember to convert to C notation
while (fgets(temp, 100, fp)) {
int row;
int value;
if (!strncmp(temp, "ARCS", 4))
break;
sscanf(temp, "%d %d", &row, &value);
upper[row-1] = -value;
lower[row-1] = -value;
}
if (strncmp(temp, "ARCS", 4)) {
fprintf(stderr, "Unable to find ARCS\n");
exit(2);
}
// number of columns may be underestimate
int * head = new int[2*numberColumns];
int * tail = new int[2*numberColumns];
int * ub = new int[2*numberColumns];
int * cost = new int[2*numberColumns];
// ***** Remember to convert to C notation
numberColumns = 0;
while (fgets(temp, 100, fp)) {
int iHead;
int iTail;
int iUb;
int iCost;
if (!strncmp(temp, "DEMAND", 6))
break;
sscanf(temp, "%d %d %d %d", &iHead, &iTail, &iCost, &iUb);
iHead--;
iTail--;
head[numberColumns] = iHead;
tail[numberColumns] = iTail;
ub[numberColumns] = iUb;
cost[numberColumns] = iCost;
numberColumns++;
}
if (strncmp(temp, "DEMAND", 6)) {
fprintf(stderr, "Unable to find DEMAND\n");
exit(2);
}
// ***** Remember to convert to C notation
while (fgets(temp, 100, fp)) {
int row;
int value;
if (!strncmp(temp, "END", 3))
break;
sscanf(temp, "%d %d", &row, &value);
upper[row-1] = value;
lower[row-1] = value;
}
if (strncmp(temp, "END", 3)) {
fprintf(stderr, "Unable to find END\n");
exit(2);
}
printf("Problem %d has %d rows and %d columns\n", problem,
numberRows, numberColumns);
fclose(fp);
ClpSimplex model;
// now build model - we have rhs so build columns - two elements
// per column
double * objective = new double[numberColumns];
double * lowerColumn = new double[numberColumns];
double * upperColumn = new double[numberColumns];
double * element = new double [2*numberColumns];
int * start = new int[numberColumns+1];
int * row = new int[2*numberColumns];
start[numberColumns] = 2 * numberColumns;
for (i = 0; i < numberColumns; i++) {
start[i] = 2 * i;
element[2*i] = -1.0;
element[2*i+1] = 1.0;
row[2*i] = head[i];
row[2*i+1] = tail[i];
lowerColumn[i] = 0.0;
upperColumn[i] = ub[i];
objective[i] = cost[i];
}
// Create Packed Matrix
CoinPackedMatrix matrix;
int * lengths = NULL;
matrix.assignMatrix(true, numberRows, numberColumns,
2 * numberColumns, element, row, start, lengths);
ClpNetworkMatrix network(matrix);
// load model
model.loadProblem(network,
lowerColumn, upperColumn, objective,
lower, upper);
delete [] lower;
delete [] upper;
delete [] head;
delete [] tail;
delete [] ub;
delete [] cost;
delete [] objective;
delete [] lowerColumn;
delete [] upperColumn;
delete [] element;
delete [] start;
delete [] row;
/* The confusing flow below is in to exercise both dual and primal
when ClpNetworkMatrix storage used.
For practical use just one call e.g. model.dual(); would be used.
If network then factorization scheme is changed
to be much faster.
Still not as fast as a real network code, but more flexible
*/
model.factorization()->maximumPivots(200 + model.numberRows() / 100);
model.factorization()->maximumPivots(1000);
//model.factorization()->maximumPivots(1);
if (model.numberRows() < 50)
model.messageHandler()->setLogLevel(63);
model.dual();
model.setOptimizationDirection(-1);
//model.messageHandler()->setLogLevel(63);
model.primal();
model.setOptimizationDirection(1);
model.primal();
return 0;
}
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