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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">Dear GROMACS Developers
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<div><span style="font-family: monospace; font-size: 16px;">My name is Asaf.</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">I'm trying to implement a novel free energy calculation method and interested to do a very minor code change.</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">I will really appreciate help on this issue.</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">What I'm trying to implement in GROMACS is very simple. It's actually only one if statement that is relevant to the VDW and Electric energies and forces.</span><br style="font-family: monospace; font-size: 16px;">
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<span style="font-family: monospace; font-size: 16px;">What is needed is to add for every calculation of energy and force:</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">If (E_VDW>Ec)</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">{</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">E_VDW=Ec;</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">f_VDW=0;</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">}</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">If (E_EL>Ec)</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">{</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">E_el=Ec;</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">f_el=0;</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">}</span><br style="font-family: monospace; font-size: 16px;">
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<span style="font-family: monospace; font-size: 16px;">where E_VDW is the energy associated with the pair VDW interaction, f_VDW is the force associated with the pair VDW potential and Ec is a constant.</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">In addition I need to multiply specific VDW and electrical forces by a const (that are associated with certain atoms).</span></div>
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<div>Could anyone advise me how to do this code change?<br style="font-family: monospace; font-size: 16px;">
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<span style="font-family: monospace; font-size: 16px;">Thanks in advance,</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">Best regards,</span><br style="font-family: monospace; font-size: 16px;">
<span style="font-family: monospace; font-size: 16px;">Asaf</span><br style="font-family: monospace; font-size: 16px;">
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