# Differences

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 damp [2010/11/02 08:16]pac079 damp [2011/11/25 03:26] (current)rowlesmr fixed some formatting and added additional 's to fix auto colouring. Both sides previous revision Previous revision 2011/11/25 03:26 rowlesmr fixed some formatting and added additional 's to fix auto colouring.2010/11/02 08:16 pac079 2010/11/02 01:00 pac079 created 2011/11/25 03:26 rowlesmr fixed some formatting and added additional 's to fix auto colouring.2010/11/02 08:16 pac079 2010/11/02 01:00 pac079 created Line 1: Line 1: ====== GSAS-style Dampening Factors ====== ====== GSAS-style Dampening Factors ====== Dampening factor for any refined value (lattice parameters, atomic positions etc.), for those who like to think that they know better than the least squares algorithm. Dampening factor for any refined value (lattice parameters, atomic positions etc.), for those who like to think that they know better than the least squares algorithm. - macro Damp(DampFactor) { update = Val + (Change*(1/​Exp(DampFactor/​2)));​ } + - '​Rather than the true GSAS dampening [applied shift = (10-damp)/​10],​ an exponential function is used, scaled to useful dampening values of 0-9 + - '​Useful dampening factors range from values of 0 (no dampening) to 9 (1% applied shift) + ''​Rather than the true GSAS dampening [applied shift = (10-damp)/​10],​ an exponential function is used, scaled to useful dampening values of 0-9 - 'List of DampFactor,​AppliedChanges:​ 0,1; 1,0.607; 2,0.368; 3,0.223; 4,0.135; 5,0.082; 6,0.50; 7,0.030; 8,0.018; 9,0.011 + ''​Useful dampening factors range from values of 0 (no dampening) to 9 (1% applied shift) - 'e.g. A simple lattice parameter refinement with dampening factors of 9, 8, 7, 6, 5, 4, 3, 2, 1 and 0 + ''List of DampFactor,​AppliedChanges:​ 0,1; 1,0.607; 2,0.368; 3,0.223; 4,0.135; 5,0.082; 6,0.50; 7,0.030; 8,0.018; 9,0.011 - ' ​    ​converges in 422, 271, 173, 111, 71, 45, 28, 17, 10 and 5 cycles, respectively + ''e.g. A simple lattice parameter refinement with dampening factors of 9, 8, 7, 6, 5, 4, 3, 2, 1 and 0 - '​Example of use: site O1 x @  0.30696 Damp(3) y 0 z 0.25 occ O-2 1 beq @ 2 Damp(7)​ + '' ​    ​converges in 422, 271, 173, 111, 71, 45, 28, 17, 10 and 5 cycles, respectively + ''​Example of use: + '' ​site O1 x @  0.30696 Damp(3) y 0 z 0.25 occ O-2 1 beq @ 2 Damp(7) + + macro Damp(DampFactor) + { + ​update = Val + (Change*(1/​Exp(DampFactor/​2)));​ + } +