void glp_std_basis(glp_prob *lp)
{ int i, j;
/* make all auxiliary variables basic */
for (i = 1; i <= lp->m; i++)
glp_set_row_stat(lp, i, GLP_BS);
/* make all structural variables non-basic */
for (j = 1; j <= lp->n; j++)
{ GLPCOL *col = lp->col[j];
if (col->type == GLP_DB && fabs(col->lb) > fabs(col->ub))
glp_set_col_stat(lp, j, GLP_NU);
else
glp_set_col_stat(lp, j, GLP_NL);
}
return;
}
int glp_read_sol(glp_prob *lp, const char *fname)
{ glp_data *data;
jmp_buf jump;
int i, j, k, ret = 0;
xprintf("Reading basic solution from '%s'...\n", fname);
data = glp_sdf_open_file(fname);
if (data == NULL)
{ ret = 1;
goto done;
}
if (setjmp(jump))
{ ret = 1;
goto done;
}
glp_sdf_set_jump(data, jump);
/* number of rows, number of columns */
k = glp_sdf_read_int(data);
if (k != lp->m)
glp_sdf_error(data, "wrong number of rows\n");
k = glp_sdf_read_int(data);
if (k != lp->n)
glp_sdf_error(data, "wrong number of columns\n");
/* primal status, dual status, objective value */
k = glp_sdf_read_int(data);
if (!(k == GLP_UNDEF || k == GLP_FEAS || k == GLP_INFEAS ||
k == GLP_NOFEAS))
glp_sdf_error(data, "invalid primal status\n");
lp->pbs_stat = k;
k = glp_sdf_read_int(data);
if (!(k == GLP_UNDEF || k == GLP_FEAS || k == GLP_INFEAS ||
k == GLP_NOFEAS))
glp_sdf_error(data, "invalid dual status\n");
lp->dbs_stat = k;
lp->obj_val = glp_sdf_read_num(data);
/* rows (auxiliary variables) */
for (i = 1; i <= lp->m; i++)
{ GLPROW *row = lp->row[i];
/* status, primal value, dual value */
k = glp_sdf_read_int(data);
if (!(k == GLP_BS || k == GLP_NL || k == GLP_NU ||
k == GLP_NF || k == GLP_NS))
glp_sdf_error(data, "invalid row status\n");
glp_set_row_stat(lp, i, k);
row->prim = glp_sdf_read_num(data);
row->dual = glp_sdf_read_num(data);
}
/* columns (structural variables) */
for (j = 1; j <= lp->n; j++)
{ GLPCOL *col = lp->col[j];
/* status, primal value, dual value */
k = glp_sdf_read_int(data);
if (!(k == GLP_BS || k == GLP_NL || k == GLP_NU ||
k == GLP_NF || k == GLP_NS))
glp_sdf_error(data, "invalid column status\n");
glp_set_col_stat(lp, j, k);
col->prim = glp_sdf_read_num(data);
col->dual = glp_sdf_read_num(data);
}
xprintf("%d lines were read\n", glp_sdf_line(data));
done:
if (ret) lp->pbs_stat = lp->dbs_stat = GLP_UNDEF;
if (data != NULL) glp_sdf_close_file(data);
return ret;
}
void glp_adv_basis(glp_prob *P, int flags)
{ int i, j, k, m, n, min_mn, size, *rn, *cn;
char *flag;
if (flags != 0)
xerror("glp_adv_basis: flags = %d; invalid flags\n", flags);
m = P->m; /* number of rows */
n = P->n; /* number of columns */
if (m == 0 || n == 0)
{ /* trivial case */
glp_std_basis(P);
goto done;
}
xprintf("Constructing initial basis...\n");
/* allocate working arrays */
min_mn = (m < n ? m : n);
rn = talloc(1+min_mn, int);
cn = talloc(1+min_mn, int);
flag = talloc(1+m, char);
/* make the basis empty */
for (i = 1; i <= m; i++)
{ flag[i] = 0;
glp_set_row_stat(P, i, GLP_NS);
}
for (j = 1; j <= n; j++)
glp_set_col_stat(P, j, GLP_NS);
/* find maximal triangular part of the constraint matrix;
to prevent including non-fixed rows and fixed columns in the
triangular part, such rows and columns are temporarily made
empty by the routine mat */
#if 1 /* FIXME: tolerance */
size = triang(m, n, mat, P, 0.001, rn, cn);
#endif
xassert(0 <= size && size <= min_mn);
/* include in the basis non-fixed structural variables, whose
columns constitute the triangular part */
for (k = 1; k <= size; k++)
{ i = rn[k];
xassert(1 <= i && i <= m);
flag[i] = 1;
j = cn[k];
xassert(1 <= j && j <= n);
glp_set_col_stat(P, j, GLP_BS);
}
/* include in the basis appropriate auxiliary variables, whose
unity columns preserve triangular form of the basis matrix */
for (i = 1; i <= m; i++)
{ if (flag[i] == 0)
{ glp_set_row_stat(P, i, GLP_BS);
if (P->row[i]->type != GLP_FX)
size++;
}
}
/* size of triangular part = (number of rows) - (number of basic
fixed auxiliary variables) */
xprintf("Size of triangular part is %d\n", size);
/* deallocate working arrays */
tfree(rn);
tfree(cn);
tfree(flag);
done: return;
}
void lpx_set_col_stat(LPX *lp, int j, int stat)
{ /* set (change) column status */
glp_set_col_stat(lp, j, stat - LPX_BS + GLP_BS);
return;
}