[GiNaC-devel] a clarification regarding the problem with simplify_indexed.

[PG CLARK]

In fact the code doesn't even care about the tensor symmetry. This  
code also fails to terminate.

#include <iostream>
#include <ginac/ginac.h>
using namespace std;
using namespace GiNaC;

int main()
{
	symbol i_sym("i"), j_sym("j"), k_sym("k"), l_sym("l"), m_sym("m"),  
n_sym("n");
	idx i(i_sym, 2), j(j_sym, 2), k(k_sym, 2), l(l_sym, 2), m(m_sym, 2),  
n(n_sym, 2);

	symbol alpha_sym("\\alpha"), beta_sym("\\beta"), gamma_sym("\\gamma");
	idx Va(alpha_sym, 3), Vb(beta_sym, 3), Vg(gamma_sym, 3);

	symbol U1("U1"), U2("U2"), U3("U3"), U4("U4"), U5("U5"), U6("U6"), h("h");

	exvector IJKLMNVec;
	idx IJKLMNIA[] ={i, j, k, l, m, n};
	IJKLMNVec.assign (IJKLMNIA,IJKLMNIA+6);

	ex myEx1 = (indexed(h, IJKLMNVec)*indexed(U1, i, Va)*indexed(U5, m, Vg)
	*indexed(U3, k, Vb)*indexed(U2, j, Va)*indexed(U4, l, Vb)*indexed(U6,  
n, Vg));

	ex myEx2 = (indexed(h, IJKLMNVec)*indexed(U1, i, Va)*indexed(U1, m, Vg)
	*indexed(U1, k, Vb)*indexed(U1, j, Va)*indexed(U1, l, Vb)*indexed(U1,  
n, Vg));

	ex myEx3 = (indexed(h, IJKLMNVec)*indexed(U1, i, Va)*indexed(U2, m, Vg)
	*indexed(U1, k, Vb)*indexed(U2, j, Va)*indexed(U1, l, Vb)*indexed(U2,  
n, Vg));

         // swap comments to see .simplify_indexed() fails in all cases
	cout << myEx2.simplify_indexed() << endl;
	//cout << myEx3.simplify_indexed() << endl;
	//cout << myEx1.simplify_indexed() << endl;

	return 0;
}

Could this be an error in simplify_indexed_product?

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