permutation: in-place inversion

2026-07-31 20:50:36 +02:00
parent 3bfa3007ce
commit e5073a3141
3 changed files with 57 additions and 1 deletions
@@ -4788,7 +4788,7 @@ cout<<tt;
 cout <<"Error = "<<(t-tt).norm()<<endl;
 }

-if(1)
+if(0)
 {
 Tensor<double> tt;
 tt.numpy_read(argv[1]);
@@ -4798,4 +4798,15 @@ cout<<"part\n"<<tt.subtensor1(1);
 cout<<"part\n"<<tt.subtensor1(2);
 }

+if(1)
+{
+int n;
+cin >>n;
+NRPerm<int> p(n); p.randomize();
+NRPerm<int> q=p.inverse();
+p.inverseme();
+if(p!=q) laerror("inverseme failed");
+else cout <<p<<"OK\n";
+}
+
 }//main