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<p style="margin-top:0;margin-bottom:0">Dear all,</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">I found an interesting wrong var assignment in ALPS MPS Project version: MAQUIS repo r4143 (2013-2014). It appears both on OSX bmg package version and builds from source code version on Linux. You can use the following
simple script to reappear the problem:</p>
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<p style="margin-top:0;margin-bottom:0">********************************************************</p>
<p># </p>
<p># Author: Rongyang Sun <sun-rongyang@outlook.com></p>
<p># Date: 2017-12-13 11:59</p>
<p># Last Modified Date: 2017-12-13 11:59</p>
<p># Last Modified By: Rongyang Sun <sun-rongyang@outlook.com></p>
<p># </p>
<p># Description: A demo to show the interesting bug</p>
<p># </p>
<p><br>
</p>
<p>import pyalps</p>
<p><br>
</p>
<p>#prepare the input parameters</p>
<p>parms = [ { </p>
<p> 'LATTICE' : "open chain lattice", </p>
<p> 'MODEL' : "spin",</p>
<p> 'CONSERVED_QUANTUMNUMBERS' : 'N,Sz',</p>
<p> 'Sz_total' : 0,</p>
<p> 'J' : 1,</p>
<p> 'spin' : 1,</p>
<p> 'SWEEPS' : 4,</p>
<p> 'NUMBER_EIGENVALUES' : 1,</p>
<p> 'L' : 10,</p>
<p> 'MAXSTATES' : 100</p>
<p> } ]</p>
<p><br>
</p>
<p>input_file = pyalps.writeInputFiles('bug',parms)</p>
<p>res = pyalps.runApplication('mps_optim',input_file,writexml=True)</p>
<p>data = pyalps.loadEigenstateMeasurements(pyalps.getResultFiles(prefix='bug'),verbose=True)</p>
<p><br>
</p>
<p>print("\nMODEL: {0}".format(str(data[0][0].props['MODEL'])))</p>
<p><br>
</p>
<p>********************************************************<br>
</p>
<p><br>
</p>
<p>It will return "MODEL: 1" not the right "MODEL" parameter because I define an unused parameter 'spin' with value 1. Once a parameter with a name which appears at the value of 'MODEL', it will be replaced by the value of the parameter. It is more severe for
't-J' model case. if you set 't': 1.0 and 'J': 0.5, 'MODEL' will be assigned as 0.5 which equals 1.0('t') - 0.5('J')! I have checked the output hdf5 file and found that the wrong replace had happened in the file. That means it may be a bug about ALPS MPS code.</p>
<p><br>
</p>
<p style="margin-top:0;margin-bottom:0">Best regards,</p>
<p style="margin-top:0;margin-bottom:0">Rongyang Sun</p>
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