+/** @file exam_collect.cpp
+ *
+ */
+
+/*
+ * GiNaC Copyright (C) 1999-2021 Johannes Gutenberg University Mainz, Germany
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "ginac.h"
+using namespace GiNaC;
+
+#include <iostream>
+using namespace std;
+
+// Correctness of .collect(Z[x], x).
+static unsigned exam_collect_1()
+{
+ unsigned result = 0;
+ symbol x("x"), y("y");
+ ex a = (pow(x, 3) - 2*pow(x, 2) + 4*x) * pow(y, 2)
+ + (pow(x, 2) - x - 1) * y
+ + (x + 1);
+ ex b = pow(y, 2) * pow(x, 3)
+ + (y - 2*pow(y, 2)) * pow(x, 2)
+ + (4*pow(y, 2) - y + 1) * x
+ + (1 - y);
+
+ ex a_x = collect(a, x);
+ if (a_x != b) {
+ clog << "collect(" << a << ", " << x << ") erroneously returned "
+ << a_x << " instead of " << b << endl;
+ ++result;
+ }
+
+ ex b_y = collect(b, y);
+ if (b_y != a) {
+ clog << "collect(" << b << ", " << y << ") erroneously returned "
+ << b_y << " instead of " << a << endl;
+ ++result;
+ }
+
+ ex amb_x = collect(a - b, x);
+ if (amb_x != 0) {
+ clog << "collect(" << a - b << ", " << x << ") erroneously returned "
+ << amb_x << " instead of 0" << endl;
+ ++result;
+ }
+
+ ex amb_y = collect(a - b, y);
+ if (amb_y != 0) {
+ clog << "collect(" << a - b << ", " << y << ") erroneously returned "
+ << amb_y << " instead of 0" << endl;
+ ++result;
+ }
+
+ return result;
+}
+
+// Consistency of .collect(Z[x,y], {x,y}) with .coeff(x).
+static unsigned exam_collect_2()
+{
+ unsigned result = 0;
+ symbol x("x"), y("y"), p("p"), q("q");
+
+ ex e1 = x + y;
+ ex e2 = 1 + p + q;
+ ex a = expand(e1 * e2);
+
+ ex a_x = a.collect(x).coeff(x, 1);
+ if (a_x != e2) {
+ clog << "collect(" << a << ", " << x << ") erroneously returned "
+ << a_x << " as coefficient of " << x << endl;
+ ++result;
+ }
+
+ ex a_p = a.collect(p).coeff(p, 1);
+ if (a_p != e1) {
+ clog << "collect(" << a << ", " << p << ") erroneously returned "
+ << a_p << " as coefficient of " << p << endl;
+ ++result;
+ }
+
+ ex a_xy = a.collect(lst{x,y});
+ ex ref = e2*x + e2*y;
+ if (a_xy != ref) {
+ clog << "collect(" << a << ", {" << x << ", " << y << "}) erroneously returned "
+ << a_xy << " instead of " << ref << endl;
+ ++result;
+ }
+
+ return result;
+}
+
+// Consistency of .collect(Z[f(x)], f(x)) with .coeff(f(x)).
+static unsigned exam_collect_3()
+{
+ unsigned result = 0;
+ symbol x("x"), p("p"), q("q");
+
+ for (unsigned deg = 2; deg < 7; ++deg) {
+
+ ex a1 = expand(pow(p + q + x, deg));
+ a1 = a1.collect(x);
+
+ ex a2 = expand(pow(p + q + sin(x), deg));
+ a2 = a2.collect(sin(x));
+
+ for (unsigned i = 0; i < deg; ++i) {
+ ex a1_i = a1.coeff(x, i);
+ ex a2_i = a2.coeff(sin(x), i);
+ if (!expand(a1_i - a2_i).is_zero()) {
+ clog << "collect(" << a1 << ",sin(x)) inconsistent with "
+ "collect(" << a2 << ",x)" << endl;
+ ++result;
+ }
+ }
+ }
+
+ return result;
+}
+
+unsigned exam_collect()
+{
+ unsigned result = 0;
+
+ cout << "examining collect coefficients" << flush;
+
+ result += exam_collect_1(); cout << '.' << flush;
+ result += exam_collect_2(); cout << '.' << flush;
+ result += exam_collect_3(); cout << '.' << flush;
+
+ return result;
+}
+
+int main(int argc, char** argv)
+{
+ return exam_collect();
+}
git://www.ginac.de / ginac.git / commitdiff