more tweaking

Author: JohnCremona

libsrc/curvered.cc

@@ -429,23 +429,22 @@ int CurveRed::ord_p_j_denom(const bigint& p) const
 int CurveRed::c_p(const bigint& p) const
 {
   auto ri = reduct_array.find(p);
-  return (ri==reduct_array.end()? : (ri->second).c_p);
+  return (ri==reduct_array.end()? 1 : (ri->second).c_p);
 }
 
 vector<bigint> CurveRed::all_cp() const
 {
-  vector<bigint> ans(reduct_array.size());
-  std::transform(reduct_array.begin(), reduct_array.end(), ans.begin(),
-                 [] (const pair<bigint,Reduction_type>& x) {return bigint(x.second.c_p);});
-  return ans;
+  vector<bigint> allcp(reduct_array.size());
+  auto cp = [] (const pair<bigint,Reduction_type>& x) {return bigint(x.second.c_p);};
+  std::transform(reduct_array.begin(), reduct_array.end(), allcp.begin(), cp);
+  return allcp;
 }
 
 bigint CurveRed::prodcp() const
 {
   static const bigint one(1);
   vector<bigint> allcp = all_cp();
-  return std::accumulate(allcp.begin(), allcp.end(), one,
-                         [](const bigint& c1, const bigint& c2) {return c1*c2;});
+  return std::accumulate(allcp.begin(), allcp.end(), one, std::multiplies<>());
 }
 
 // The local Tamagawa number.  Use p=0 for reals
@@ -526,10 +525,9 @@ int CurveRed::LocalRootNumber(const bigint& p) const
 
 int CurveRed::GlobalRootNumber() const
 {
-  int ans=-1; // root number at the infinte place (which is real)
-  for( const auto& ri : reduct_array)
-    ans *= (ri.second).local_root_number;
-  return ans;
+  auto rn = [](const std::pair<bigint,Reduction_type>& ri){return (ri.second).local_root_number;};
+  return std::transform_reduce(reduct_array.cbegin(), reduct_array.cend(),
+                               -1, std::multiplies<>(), rn);
 }
 
 int kro(const bigint& d, const bigint& n);

libsrc/eclib/marith.h

@@ -292,6 +292,8 @@ class divisor_iterator {
 
 // [n^e for 0 <= e <= maxexp]
 vector<bigint> powers(const bigint& n, int maxexp);
+// [n^e for e in exponents]
+vector<bigint> powers(const bigint& n, const vector<int>& exponents);
 
 // Compute N from its factorization (lists of primes and exponents) --
 // (name taken from gp)

libsrc/marith.cc

@@ -1184,8 +1184,8 @@ int is_nth_power(const bigint& x, int n)
   if ((x<0) && (n%2==0))
     return 0;
   vector<bigint> plist = pdivs(x);
-  return std::all_of(plist.begin(), plist.end(),
-                     [n,x](const bigint& p){return val(p,x)%n==0;});
+  auto local_condition = [n,x](const bigint& p){return val(p,x)%n==0;};
+  return std::all_of(plist.begin(), plist.end(), local_condition);
 }
 
 bigint prime_to_S_part(const bigint& x,  const vector<bigint>& S)
@@ -1279,36 +1279,37 @@ vector<bigint> powers(const bigint& n, int maxexp)
   bigint np(1);
   npowers[0] = np;
   int e = 0;
-  std::generate(npowers.begin()+1, npowers.end(),
-                [n, &np, &e](){np*=n; e++; return np;});
+  auto next_power = [n, &np, &e](){np*=n; e++; return np;};
+  std::generate(npowers.begin()+1, npowers.end(), next_power);
   return npowers;
 }
 
 // [n^e for e in exponents]
 vector<bigint> powers(const bigint& n, const vector<int>& exponents)
 {
   vector<bigint> npowers(exponents.size());
-  auto e = exponents.begin();
-  std::generate(npowers.begin(), npowers.end(),
-                [n, &e](){return pow(n, *e++);;});
+  auto npower = [n](int e){return pow(n,e);};
+  std::transform(exponents.cbegin(), exponents.cend(), npowers.begin(), npower);
   return npowers;
 }
 
 // Compute N from its factorization (lists of primes and exponents) --
 // (name taken from gp)
 bigint factorback(const vector<bigint>&PP, const vector<int>& EE)
 {
+  static const bigint one(1);
+  auto power = [](const bigint& p, int e){return pow(p,e);};
   return std::transform_reduce(PP.cbegin(), PP.cend(), EE.cbegin(),
-                               bigint(1),                                   // initial value
-                               std::multiplies<>(),                         // how to combine terms,
-                               [](const bigint& p, int e){return pow(p,e);} // how to form terms
-                               );
+                               one,                  // initial value
+                               std::multiplies<>(),  // how to combine terms,
+                               power);               // how to form terms
 }
 
 // Maximum conductor for a given list of primes
 bigint MaxN(const vector<bigint>&PP)
 {
-  bigint N(1);
+  static const bigint one(1);
+  bigint N(one);
   std::for_each(PP.cbegin(), PP.cend(),
                [&N](const bigint& p){N *= pow(p, (p==2?8:p==3?5:2));});
   return N;
@@ -1325,8 +1326,8 @@ bigint radical(const bigint& N)
 vector<bigint> multiply_list(const bigint& a, const vector<bigint>& L)
 {
   vector<bigint> aL(L.size());
-  std::transform(L.begin(), L.end(), aL.begin(),
-                 [a](const bigint& x){return a*x;});
+  auto times_a = [a](const bigint& x){return a*x;};
+  std::transform(L.begin(), L.end(), aL.begin(), times_a);
   return aL;
 }
 
@@ -1354,7 +1355,8 @@ vector<bigint> multiply_list_by_powers(const bigint& p, const vector<int>& expon
 vector<bigint> bigintify(const vector<long>& L)
 {
   vector<bigint> LL(L.size());
-  std::transform(L.cbegin(), L.cend(), LL.begin(), [](long x){return bigint(x);});
+  auto long2big = [](long x){return bigint(x);};
+  std::transform(L.cbegin(), L.cend(), LL.begin(), long2big);
   return LL;
 }
 

tests/mptest.cc

@@ -109,6 +109,9 @@ int main()
   cout << "\nTesting list multiplication functions\n";
   vector<bigint> powers_of_2 = powers(bigint(2), 10);
   cout << "Powers of 2 up to 2^10: " << powers_of_2 << endl;
+  //  vector<int> odds = {1,3,5,7,9};
+  vector<bigint> odd_powers_of_2 = powers(bigint(2), {1,3,5,7,9});
+  cout << "Odd powers of 2 up to 2^10: " << odd_powers_of_2 << endl;
 
   vector<bigint> L = bigintify({1,2,3,4,5});
   cout << "L   = " << L << endl;
@@ -169,9 +172,9 @@ int main()
      cout << "m = " << m << endl;
      vector<bigint> plist=pdivs(m);
      cout << "m has " << plist.size() << " prime divisors: " << plist << endl;
-     vector<int> ee = valuations(m, plist);
-     cout << "with exponents " << ee << endl;
-     bigint m2 = factorback(plist, ee);
+     vector<int> vals = valuations(m, plist);
+     cout << "with exponents " << vals << endl;
+     bigint m2 = factorback(plist, vals);
      cout << "factorback recovers " << m2 << " (should be " << m << ")" << endl;
 
      vector<bigint> dlist=alldivs(m,plist);

tests/out_no_ntl/mptest.out

@@ -37,6 +37,7 @@ testing find function for the list [ 1 -1 2 -2 4 -4 3 -3 6 -6 12 -12 5 -5 10 -10
 
 Testing list multiplication functions
 Powers of 2 up to 2^10: [ 1 2 4 8 16 32 64 128 256 512 1024 ]
+Odd powers of 2 up to 2^10: [ 2 8 32 128 512 ]
 L   = [ 1 2 3 4 5 ]
 3*L = [ 3 6 9 12 15 ]
 L2   = [ 1 10 100 ]

tests/out_ntl/mptest.out

@@ -37,6 +37,7 @@ testing find function for the list [ 1 -1 2 -2 4 -4 3 -3 6 -6 12 -12 5 -5 10 -10
 
 Testing list multiplication functions
 Powers of 2 up to 2^10: [ 1 2 4 8 16 32 64 128 256 512 1024 ]
+Odd powers of 2 up to 2^10: [ 2 8 32 128 512 ]
 L   = [ 1 2 3 4 5 ]
 3*L = [ 3 6 9 12 15 ]
 L2   = [ 1 10 100 ]

tests/tegros.cc

@@ -56,13 +56,13 @@ int main(void)
   vector<CurveRed> egr_S23_0 = egros_from_j_0(S23);
   std::sort(egr_S23_0.begin(), egr_S23_0.end());
   cout << egr_S23_0.size()<< " curves with j=0 and good reduction outside "<<S23<<" (should be 72):\n";
-  for (auto E: egr_S23_0) cout<<(Curve)E<<" conductor "<<E.conductor()<<" sort key "<<E.sort_key()<<endl;
+  for (auto E1: egr_S23_0) cout<<(Curve)E1<<" conductor "<<E1.conductor()<<" sort key "<<E1.sort_key()<<endl;
   cout<<endl;
 
   vector<CurveRed> egr_S23_1728 = egros_from_j_1728(S23);
   std::sort(egr_S23_1728.begin(), egr_S23_1728.end());
   cout << egr_S23_1728.size()<< " curves with j=1728 and good reduction outside "<<S23<<" (should be 32):\n";
-  for (auto E: egr_S23_1728) cout<<(Curve)E<<" conductor "<<E.conductor()<<" sort key "<<E.sort_key()<<endl;
+  for (auto E1: egr_S23_1728) cout<<(Curve)E1<<" conductor "<<E1.conductor()<<" sort key "<<E1.sort_key()<<endl;
   cout<<endl;
 
   cout << "Elliptic curves with conductor a power of 11, from their known j-invariants" << endl;
@@ -75,18 +75,18 @@ int main(void)
     bigrational(bigint(-24729001))
   };
   vector<CurveRed> egr_11;
-  for (auto j: j11)
+  for (auto ji: j11)
     {
-      auto EE = egros_from_j(j, S11);
-      cout << EE.size() << " curves with j = " << j << ":";
-      for ( auto E: EE) cout << " " << (Curve)E;
+      auto EE = egros_from_j(ji, S11);
+      cout << EE.size() << " curves with j = " << ji << ":";
+      for ( auto E1: EE) cout << " " << (Curve)E1;
       cout << endl;
       egr_11.insert(egr_11.end(), EE.cbegin(), EE.cend());
     }
   std::sort(egr_11.begin(), egr_11.end());
   cout<<"Sorted list:\n";
-  for (auto E: egr_11)
-    cout << "conductor " << E.conductor() << "\t" << (Curve)E << "\tj = " << j_invariant(E) << endl;
+  for (auto E1: egr_11)
+    cout << "conductor " << E1.conductor() << "\t" << (Curve)E1 << "\tj = " << j_invariant(E1) << endl;
   cout << endl;
 
   vector<bigint> N_j_0, N_j_1728;
@@ -100,27 +100,27 @@ int main(void)
         {
           N_j_0.push_back(N);
           auto EE = egros_from_j_0(S);
-          for (auto E: EE)
-            if (E.conductor()==N)
-              E_j_0.push_back(E);
+          for (auto E1: EE)
+            if (E1.conductor()==N)
+              E_j_0.push_back(E1);
         }
       if (is_N_possible_j_1728(N, S))
         {
           N_j_1728.push_back(N);
           auto EE = egros_from_j_1728(S);
-          for (auto E: EE)
-            if (E.conductor()==N)
-              E_j_1728.push_back(E);
+          for (auto E1: EE)
+            if (E1.conductor()==N)
+              E_j_1728.push_back(E1);
         }
     }
   cout << "Possible conductors <= 100 of curves with j=0:    " << N_j_0 << endl;
   cout << "Actual conductors and curves:\n";
-  for (auto E: E_j_0)
-    cout << E.conductor() << "\t" << (Curve)E << endl;
+  for (auto E1: E_j_0)
+    cout << E1.conductor() << "\t" << (Curve)E1 << endl;
   cout << "Possible conductors < 100 of curves with j=1728: " << N_j_1728 << endl;
   cout << "Actual conductors and curves:\n";
-  for (auto E: E_j_1728)
-    cout << E.conductor() << "\t" << (Curve)E << endl;
+  for (auto E1: E_j_1728)
+    cout << E1.conductor() << "\t" << (Curve)E1 << endl;
 
   return 0;
 }