From 641b632df192d58ab975d8ab5f5f2b50c137fc1a Mon Sep 17 00:00:00 2001
From: Jiri Pittner <jiri@pittnerovi.com>
Date: Tue, 11 Nov 2025 19:48:44 +0100
Subject: [PATCH] tensor: special cases of ourter product with trivial tensor

---
 t.cc      | 23 ++++++++++++++++++++++-
 tensor.cc |  1 +
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/t.cc b/t.cc
index 0a866c5..02e1488 100644
--- a/t.cc
+++ b/t.cc
@@ -4091,7 +4091,7 @@ for(int i=0;i<n+1;++i) for(int j=0;j<n+2;++j)
 cout <<"Error= "<<e<<endl;
 }
 
-if(1)
+if(0)
 {
 int r=4;
 int n=5;
@@ -4120,5 +4120,26 @@ Tensor<double> ss(s);
 cout <<"Error= "<<ss-xc<<endl;
 }
 
+if(1)
+{
+int r=1;
+int n=5;
+NRVec<INDEXGROUP> sh(r);
+for(int i=0; i<r; ++i)
+        {
+        sh[i].number=1;
+        sh[i].symmetry=0;
+        sh[i].range=n;
+        sh[i].offset=0;
+        }
+Tensor<double> x(sh); x.randomize(1.);
+Tensor<double> s1(2.);
+Tensor<double> s2(3.);
+cout <<s1*x<<endl;
+cout <<x*s1<<endl;
+cout<<s1*s2<<endl;
+}
+
+
 
 }//main
diff --git a/tensor.cc b/tensor.cc
index 9b2831e..5273d17 100644
--- a/tensor.cc
+++ b/tensor.cc
@@ -1831,6 +1831,7 @@ return r;
 template<typename T>
 void Tensor<T>::canonicalize_shape()
 {
+if(shape.size()==0) return;
 const INDEXGROUP *sh = &(* const_cast<const NRVec<INDEXGROUP> *>(&shape))[0];
 for(int i=0; i<shape.size(); ++i)
 	{