mirror of https://gitlab.com/QEF/q-e.git
65 lines
4.2 KiB
Plaintext
65 lines
4.2 KiB
Plaintext
!=========================================================================!
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! README.WANNIER !
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! Author: Manu Sharma !
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! msharma@alumni.Princeton.EDU !
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!=========================================================================!
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! INPUT FORMAT FOR WFDD.X !
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!=========================================================================!
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! This code was originally written by Yudong Wu and later modified by !
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! Manu Sharma. This is intended to be a post-processing code and the !
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! search for the appropriate Unitary transformation can be done using not !
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! only damped-dynamics, but also Steepest descent and conjugate gradient !
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! algorithms. The advantage !
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! is that SD/CG can serve as benchmarks to make sure that the DD is !
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! converging to the correct values (in deciding the parameters Q and DT !
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! for the DD). The disadvantage is that SD/CG schemes are slower than !
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! the DD. It is useful however, before using DD in production runs, to !
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! make sure that the parameters (Q and DT) give the same answer as the SD !
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! or CG. This code requires as input, the overlap matrix. This can be !
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! calculated from the CP code by setting CALWF to 2 in the &WANNIER !
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! namelist (The defaukt value is 3, for Wannier dynamics. This option !
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! outputs the overlap matrix to unit 38, and wfdd.x reads it from the same!
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! file. !
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! In addition to that, you need an input file of the following form. !
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! !
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! !
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! 1 0.3 0.5 100 10 CGORDD WFDT MAXWFDT NIT NSD !
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! 1500 5.0 0.3 .true. 100 1.0d-8 Q DT FRIC ADAPT NSTEPS TOLW !
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! .true. RESTART !
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! !
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! CGORDD : Whether to do SD/CG optimization of damped dynamics !
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! Can take the values 1 or 2. 1 means SD/CG and 2 means DD !
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! WFDT : Used when GCORDD=1. This is the step length you take in the !
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! direction of steepest descent. !
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! MAXWFDT: Used when CGORDD=1. This is the maximum step length you take !
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! in the direction if steepest descent. if WFDT or MAXWFDT are !
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! large, the calculation will not converge. The code uses the !
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! parabolic approximation to estimate the appropriate step length!
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! and if it is less than WFDT, then WFDT is taken as the step !
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! length and if more than MAXWFDT then MAXWFDT is taken as the !
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! Step length. !
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! NIT : Used when CGORDD=1. This is the maxumum number of iterations !
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! to do. !
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! NSD : Used whdn CGORDD=1. This is the number of Steepest descent !
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! steps to do. If NSD = NIT then it is a pure SD optimization !
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! If NSD < NIT, then the code first does NSD Steepest descent !
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! steps and then NIT-NSD Conjugate gradient steps. !
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! RESTART: Use this option to continue a SD/CG/DD optimization. This !
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! option reads the Unitray transform from fort.39, written at the!
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! end of the last run and continues from there. !
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! !
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! The other are used for the Damped dynamics and are defined !
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! in the INPUT_CP file in the Doc/ directory under NAMELIST &WANNIER. !
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! !
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! The program may be compiled by make wfdd.x and then run as follows !
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! ./wfdd.x < [input-filename] > [output-filename] & !
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! The output file will contain the inverse spread (which is the functional!
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! that is actually maximized in the code rather than minimizing the !
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! spread) at each step of the optimization. !
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! !
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! Manu Sharma !
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! February 14th,2006 !
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!=========================================================================!
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! COPYRIGHT MANU SHARMA/YUDONG WU/NICOLA MARZARI/ROBERTO CAR !
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!=========================================================================!
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