+ g_assert_cmpuint(iArray->len, ==, jArray->len);
+ g_assert_cmpuint(jArray->len, ==, aArray->len);
+ g_assert_cmpuint(aArray->len - 1, ==, hullPointNb * 2);
+
+ glp_load_matrix(lp, aArray->len - 1, &g_array_index(iArray, int, 0),
+ &g_array_index(jArray, int, 0), &g_array_index(aArray, double, 0));
+
+ glp_scale_prob(lp, GLP_SF_AUTO);
+
+ g_array_free(iArray, TRUE);
+ g_array_free(jArray, TRUE);
+ g_array_free(aArray, TRUE);
+
+ return lp;
+}
+
+
+/*
+ * A GFunc for g_queue_foreach(). Add constraints and bounds for one row.
+ *
+ * Args:
+ * data Point*, synchronization point for which to add an LP row
+ * (a constraint)
+ * user_data LPAddRowInfo*
+ */
+static void gfLPAddRow(gpointer data, gpointer user_data)
+{
+ Point* p= data;
+ struct LPAddRowInfo* rowInfo= user_data;
+ int indexes[2];
+ double constraints[2];
+
+ indexes[0]= g_array_index(rowInfo->iArray, int, rowInfo->iArray->len - 1) + 1;
+ indexes[1]= indexes[0];
+
+ if (rowInfo->boundType == GLP_UP)
+ {
+ glp_set_row_bnds(rowInfo->lp, indexes[0], GLP_UP, 0., p->y);
+ }
+ else if (rowInfo->boundType == GLP_LO)
+ {
+ glp_set_row_bnds(rowInfo->lp, indexes[0], GLP_LO, p->y, 0.);
+ }
+ else
+ {
+ g_assert_not_reached();
+ }
+
+ g_array_append_vals(rowInfo->iArray, indexes, 2);
+ indexes[0]= 1;
+ indexes[1]= 2;
+ g_array_append_vals(rowInfo->jArray, indexes, 2);
+ constraints[0]= 1.;
+ constraints[1]= p->x;
+ g_array_append_vals(rowInfo->aArray, constraints, 2);
+}
+
+
+/*
+ * Calculate min or max correction factors (as possible) using an LP problem.
+ *
+ * Args:
+ * lp: A linear programming problem with constraints and bounds
+ * initialized.
+ * direction: The type of factors desired. Use GLP_MAX for max
+ * approximation factors (a1, the drift or slope is the
+ * largest) and GLP_MIN in the other case.
+ *
+ * Returns:
+ * If the calculation was successful, a new Factors struct. Otherwise, NULL.
+ * The calculation will fail if the hull assumptions are not respected.
+ */
+static Factors* calculateFactorsLP(glp_prob* const lp, const int direction)
+{
+ int retval, status;
+ Factors* factors;
+
+ glp_set_obj_coef(lp, 1, 0.);
+ glp_set_obj_coef(lp, 2, 1.);
+
+ glp_set_obj_dir(lp, direction);
+ retval= glp_simplex(lp, NULL);
+ status= glp_get_status(lp);
+
+ if (retval == 0 && status == GLP_OPT)
+ {
+ factors= malloc(sizeof(Factors));
+ factors->offset= glp_get_col_prim(lp, 1);
+ factors->drift= glp_get_col_prim(lp, 2);
+ }
+ else