docs:classes:fieldsymmetry
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docs:classes:fieldsymmetry [2009/02/16 16:29] wikiadmin |
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| - | ====== Constructors / Initialization ====== | + | The following is a brief overview of FieldSymmetry functionality. For a complete description, |
| + | see the header file {{:librarycode:symmetry.h}}. | ||
| + | ===== Constructors / Initialization ===== | ||
| In C++ code, elements of the symmetry group can initialized as follows, | In C++ code, elements of the symmetry group can initialized as follows, | ||
| Line 45: | Line 47: | ||
| FieldSymmetry identity; // the identity: s defaults to 1; ax,az to 0; sx,sy,sz to 1 | FieldSymmetry identity; // the identity: s defaults to 1; ax,az to 0; sx,sy,sz to 1 | ||
| </code> | </code> | ||
| - | |||
| ===== Operations ===== | ===== Operations ===== | ||
| Line 79: | Line 80: | ||
| ... | ... | ||
| </code> | </code> | ||
| + | ===== ASCII IO ===== | ||
| + | ==== FieldSymmetry ==== | ||
| - | For a complete description of the FieldSymmetry class, see the header file fieldsymmetry.h. | + | The FieldSymmetry uses ASCII input-output. The storage format is |
| + | s sx sy sz ax az | ||
| + | Thus, the following C++ channelflow code | ||
| + | |||
| + | <code c++> | ||
| + | FieldSymmetry sigma(-1, -1, -1, 0.3, 0.1); | ||
| + | sigma.save("sigma"); | ||
| + | </code> | ||
| + | |||
| + | produces the ASCII file ''sigma.asc'' with contents | ||
| + | |||
| + | 1 -1 -1 -1 0.3 0.1 | ||
| + | |||
| + | which can then be read back into a channeflow program with | ||
| + | |||
| + | <code c++> | ||
| + | FieldSymmetry sigma("sigma"); | ||
| + | </code> | ||
| + | |||
| + | Note that the order of parameters in the ASCII file is different than the order in the ''FieldSymmetry'' constructor: the overall multiplicative sign ''s'' goes first in the file and last in the C++ constructor. I apologize for this. The reasons for the difference are are historical. The next release of channelflow will have order (s, sx, sy, sz, ax, az) for both. | ||
| + | |||
| + | ==== SymmetryList ==== | ||
| + | |||
| + | The ''SymmetryList'' class is a essentially an array of ''FieldSymmetry'' objects with simple ASCII IO methods. The ASCII format is | ||
| + | |||
| + | % N | ||
| + | s0 sx0 sy0 sz0 ax0 az0 | ||
| + | s1 sx1 sy1 sz1 ax1 az1 | ||
| + | ... | ||
| + | |||
| + | where N is the number of symmetries listed in the file. Thus the file ''S.asc'' with contents | ||
| + | |||
| + | % 2 | ||
| + | 1 1 1 -1 0.5 0.0 | ||
| + | 1 -1 -1 1 0.5 0.5 | ||
| + | |||
| + | represents the symmetries σ0 = (1, 1, 1, -1, 0.5, 0.0) and σ1 = (1, -1, -1, 1, 0.5, 0.5). These are the generators of the S | ||
| + | [[docs:math:symmetry#isotropy_groups_of_known_solutions|S symmetry group]]. The generators can be loaded into channelflow, used, and saved as follows | ||
| + | |||
| + | <code c++> | ||
| + | SymmetryList S("S"); // load generators from ASCII file | ||
| + | FlowField foo = S[0](u); // apply (1, 1, 1, -1, 0.5, 0.0) to u | ||
| + | FlowField bar = S[1](u); // apply (1, -1, -1, 1, 0.5, 0.5) to u | ||
| + | S.save("Q"); // save generators into another file | ||
| + | |||
| + | SymmetryList P(4); // Create another symmetry group | ||
| + | P[0] = FieldSymmetry(1,1,1, 0.2, 0.0); | ||
| + | P[1] = etc.; | ||
| + | </code> | ||
| + | | ||
docs/classes/fieldsymmetry.1234830549.txt.gz · Last modified: 2009/02/16 16:29 by wikiadmin
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