My mistake. The answer is available on the previously mentioned page and the tutorial page: http://alps.comp-phys.org/mediawiki/index.php/ALPS_2_Tutorials:DMRG-04_Correlations

If the non-local operator "X" is defined in the file /opt/alps/lib/xml/models.xml, then its average value will be evaluated by an extra line in the parms dictionary:

parms.append( {
...
'MEASURE_AVERAGE[X]' : 'X',
...
} )

rgrds,
Pradeep.

On 12 July 2014 14:54, pradeep thakur <pskvkthakur@gmail.com> wrote:

Dear All,

I'm running the dmrg application and am wanting to measure the average of a bond-operator. How to measure the average value of an operator that contains non-local terms like S(i)plus*S(i+1)minus or S(i)plus*S(i+2)minus?

Also is it possible to measure the value of such operators separately for each bond, the way we measure "local" operators for each site?

http://alps.comp-phys.org/mediawiki/index.php/Tutorials:MeasureHOWTO This page says that it is not possible to do this, as of now. Have there been any recent developments to the contrary?

Thank you for your time. Really grateful for any clarification provided.

regards,
Pradeep Thakur,
University of Pune, Pune, INDIA.