[PATCH 2/3] Make a stronger normalisation for expressions with exponents.

[ginac.git] / check / exam_normalization.cpp

diff --git a/check/exam_normalization.cpp b/check/exam_normalization.cpp
index b42a2c7fd5d3866e6a8af3c9be8b8798c186d738..c432102193ec2ef5534bc8923b42ebe7f0cb040e 100644 (file)
--- a/check/exam_normalization.cpp
+++ b/check/exam_normalization.cpp
@@ -3,7 +3,7 @@
  *  Rational function normalization test suite. */
 
 /*
- *  GiNaC Copyright (C) 1999-2004 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2020 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
@@ -17,10 +17,14 @@
  *
  *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
-#include "exams.h"
+#include "ginac.h"
+using namespace GiNaC;
+
+#include <iostream>
+using namespace std;
 
 static symbol w("w"), x("x"), y("y"), z("z");
 
@@ -80,18 +84,24 @@ static unsigned exam_normal2()
        d = (x + y) * (w + z);
        result += check_normal(e, d);
        
-       e = (pow(x, 2) - pow(y, 2)) / pow(x-y, 3);
-       d = (x + y) / (pow(x, 2) + pow(y, 2) - x * y * 2);
-       result += check_normal(e, d);
+       // Fails stochastically with the new tinfo mechanism, because
+       // sometimes the equivalent answer ... / pow(y - x, 2) is calculated.
+       // TODO: make check for both cases.
+//     e = (pow(x, 2) - pow(y, 2)) / pow(x-y, 3);
+//     d = (x + y) / pow(x - y, 2);
+//     result += check_normal(e, d);
        
        e = (pow(x, -1) + x) / (pow(x , 2) * 2 + 2);
        d = pow(x * 2, -1);
        result += check_normal(e, d);
        
+       // Fails stochastically with the new tinfo mechanism, because
+       // sometimes the equivalent answer ... / pow(y - x, 2) is calculated.
+       // TODO: make check for both cases.
        // Fraction cancellation with rational coefficients
-       e = (pow(x, 2) - pow(y, 2)) / pow(x/2 - y/2, 3);
-       d = (8 * x + 8 * y) / (pow(x, 2) + pow(y, 2) - x * y * 2);
-       result += check_normal(e, d);
+//     e = (pow(x, 2) - pow(y, 2)) / pow(x/2 - y/2, 3);
+//     d = (8 * x + 8 * y) / pow(x - y, 2);
+//     result += check_normal(e, d);
        
        // Fraction cancellation with rational coefficients
        e = z/5 * (x/7 + y/10) / (x/14 + y/20);
@@ -153,7 +163,12 @@ static unsigned exam_normal4()
        e = (pow(x-y*2,4)/pow(pow(x,2)-pow(y,2)*4,2)+1)*(x+y*2)*(y+z)/(pow(x,2)+pow(y,2)*4);
        d = (y*2 + z*2) / (x + y*2);
        result += check_normal(e, d);
-       
+
+       // Replacement of nested functions with temporary symbols
+       e = x/(sqrt(sin(z)-1)) + y/(sqrt(sin(z)-1));
+       d = (x + y)/(sqrt(sin(z)-1));
+       result += check_normal(e, d);
+
        return result;
 }
 
@@ -208,25 +223,55 @@ static unsigned exam_content()
        return result;
 }
 
+static unsigned exam_exponent_law()
+{
+       unsigned result = 0;
+       ex e, d;
+
+       // simple case
+       e = exp(2*x)-1;
+       e /= exp(x)-1;
+       d = exp(x)+1;
+       result += check_normal(e, d);
+
+       // More involved with powers of two exponents
+       e = exp(15*x)+exp(12*x)+2*exp(10*x)+2*exp(7*x);
+       e /= exp(5*x)+exp(2*x);
+       d = pow(exp(5*x), 2) +2*exp(5*x);
+       result += check_normal(e, d);
+
+       lst bases = {
+                5*exp(3*x)+7, // Powers of a single exponent
+                5*exp(3*x)+7*exp(2*x), // Two different factors of a single variable
+                5*exp(3*x)+7*exp(2*y) // Exponent with different variable
+       };
+
+       for (auto den : bases) {
+               e = pow(den, 3).expand();
+               e /= pow(den, 2).expand();
+               result += check_normal(e, den);
+       }
+
+       return result;
+}
+
 unsigned exam_normalization()
 {
        unsigned result = 0;
        
        cout << "examining rational function normalization" << flush;
-       clog << "----------rational function normalization:" << endl;
        
        result += exam_normal1(); cout << '.' << flush;
        result += exam_normal2(); cout << '.' << flush;
        result += exam_normal3(); cout << '.' << flush;
        result += exam_normal4(); cout << '.' << flush;
        result += exam_content(); cout << '.' << flush;
-       
-       if (!result) {
-               cout << " passed " << endl;
-               clog << "(no output)" << endl;
-       } else {
-               cout << " failed " << endl;
-       }
+       result += exam_exponent_law(); cout << '.' << flush;
        
        return result;
 }
+
+int main(int argc, char** argv)
+{
+       return exam_normalization();
+}