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docs:utils:findorbit [2009/02/11 08:03]
gibson
docs:utils:findorbit [2009/06/08 06:40]
gibson
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   -Ng       ​--Ngmres ​           <​int> ​      ​default == 40          max number of GMRES iterations per restart   -Ng       ​--Ngmres ​           <​int> ​      ​default == 40          max number of GMRES iterations per restart
   -d        --delta ​            <​real> ​     default == 0.01        initial radius of trust region   -d        --delta ​            <​real> ​     default == 0.01        initial radius of trust region
-  -sx       --x-sign ​                                              ​change u,x sign +  -sigma    ​--sigma             <string                          file containing symmetry of relative eqb/orb 
-  -sy       ​--y-sign ​                                              ​change v,y sign +  -symms    ​--symmetries ​       ​<string                          constrain u(t) to invariant subspace generated ​by symmetries in listed file, arg is filename
-  -sz       ​--z-sign ​                                              ​change w,z sign +
-  -ax       ​--axshift ​          <real     ​default == 0           ​translate by ax*Lx +
-  -az       --azshift ​          <real     ​default == 0           ​translate ​by az*Lz+
   -R        --Reynolds ​         <​real> ​     default == 400         ​Reynolds number   -R        --Reynolds ​         <​real> ​     default == 400         ​Reynolds number
   -vdt      --variableDt ​                                          ​adjust dt to keep CFLmin<​=CFL<​CFLmax   -vdt      --variableDt ​                                          ​adjust dt to keep CFLmin<​=CFL<​CFLmax
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   * -eqb leaves the integration time fixed   * -eqb leaves the integration time fixed
   * -orb adds the integration time T to the search space   * -orb adds the integration time T to the search space
-  * -rel modifies -orb / -eqb, makes the search for a relative periodic orbit or relative equilibrium (traveling wave), by adding ​the finite-time phase shift variables ''​ax''​ and ''​az''​ to the search space +  * -rel modifies -orb / -eqb, makes the search for a relative periodic orbit or relative equilibrium (traveling wave), by adding finite-time phase shift variables ''​ax''​ and ''​az''​ to the search space 
-  * -ax and -az specify a fixed or initial guess finite-time phase shifts for the solution ​(depending on whether ​-rel is specified)+  * -sigma <​filename>​ sets the initial guess (if -rel) or fixed value (if not -rel) of the symmetry \sigma  
 +  * -symms <​filename>​ constrains the search to an invariant subspace. The file is a list of generators for the isotropy group.  ​
  
 In all cases we search for a solution of  In all cases we search for a solution of 
  
 <​latex>​ <​latex>​
- \tau_{a_x, a_z} f^T(u) - u = 0+ \sigma f^T(u) - u = 0
 </​latex>​ </​latex>​
  
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 <​latex>​ <​latex>​
-  \tau_{a_x, a_z} [u,​v,​w](x,​y,​z) \rightarrow [u,​v,​w](x+a_x/​L_x,​ \, y, \, z+a_z/L_z)+  \sigma [u,​v,​w](x,​y,​z) \rightarrow ​[s_x u, \, s_y v, \, s_z w](s_x x + a_x/L_x, \, s_y y, \, s_z z + a_z/L_z)
 </​latex>​ </​latex>​
  
-Further symmetry operations are available but not yet documented.+(will continue later today.... /2009-06-08 jfg)
  
-===== Usage examples =====+====== Usage examples ​======
  
-==== equilibrium ====+===== equilibrium ​=====
 Find an equilibrium from initial guess ''​guess.ff''​ Find an equilibrium from initial guess ''​guess.ff''​
 <​code>​ <​code>​
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 </​code>​ </​code>​
  
-==== traveling wave ====+===== traveling wave =====
 Find a traveling wave (relative equilibrium) from initial guess ''​guess.ff'',​ with initial guess for wavespeed Find a traveling wave (relative equilibrium) from initial guess ''​guess.ff'',​ with initial guess for wavespeed
 specified in terms of finite shifts (ax/Lx, az/Lz) in finite time T. Equivalent to wavespeed (cx, cz) =  1/T (ax/Lx, az/Lz). specified in terms of finite shifts (ax/Lx, az/Lz) in finite time T. Equivalent to wavespeed (cx, cz) =  1/T (ax/Lx, az/Lz).
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 the ''​--rel''​ option adds the finite shift variables (ax, az) to the search space. the ''​--rel''​ option adds the finite shift variables (ax, az) to the search space.
  
-==== periodic orbit ====+===== periodic orbit =====
 Find a periodic orbit with initial guess for period T=83 Find a periodic orbit with initial guess for period T=83
 <​code>​ <​code>​
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 </​code>​ </​code>​
  
-==== relative periodic orbit ===+===== relative periodic orbit ====
 Find a relative periodic orbit with initial guess of a shift by Lz/4 every period T=83 Find a relative periodic orbit with initial guess of a shift by Lz/4 every period T=83
 <​code>​ <​code>​
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 </​code>​ </​code>​
  
-It takes a small amount of thinking to determine the right -orb, -eqb, -rel, -ax, and -az options based on the type of +It takes half minute'​s ​thinking to determine the right -orb, -eqb, -rel, -ax, and -az options based on the type of search you want.
-search you want and +
  
 ====== Mathematics ====== ====== Mathematics ======
docs/utils/findorbit.txt · Last modified: 2010/02/02 07:55 (external edit)