Control an enumeration¶

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Starting point: You can construct an SSAGenerator and run the quickstart search.
Destination: You can choose the five search controls deliberately.
Next: Check the implemented relations in Enumeration and equivalence when candidate counts need explanation.
Skip: The quickstart settings already cover your calculation.

Start with the smallest relevant search¶

Select the moment geometry required by the problem, then keep the default equivalence reductions:

from spinspg.spin import SpinOnlyGroupType

candidates = generator.enumerate(
    spin_only_group_type=SpinOnlyGroupType.COLLINEAR,
    k_index=1,
    max_depth=0,
    up_to_parent_conjugacy=True,
)

Use COLLINEAR, COPLANAR, or NONCOPLANAR according to the moment geometry you intend to model. Moving to a less restrictive type changes the physical search, not merely its cost.

Set the translation bound¶

Without measured propagation vectors, k_index is required. It is the index of the final invariant translation lattice that bounds enumeration:

k_index=1 restricts the final lattice to the primitive translation lattice.
A larger value admits compatible family translation lattices whose indices divide that value.

If commensurate propagation vectors are known, construct the generator with SSAGenerator.with_propagation_vectors() instead. SpinForge then derives the lattice and supplies its index automatically; follow Constrain an enumeration with propagation vectors.

Set the Hermann depth¶

max_depth controls which translationengleiche Hermann groups are searched. Their bounded klassengleiche descendants remain included.

Value	Hermann groups retained
`0`	Parent only
`1`	Parent and maximal proper subgroups (default)
`None`	All subgroup depths

Begin at 0 when validating a workflow. Increase the depth only when the target family symmetry requires it.

Choose the spatial reduction¶

Keep up_to_parent_conjugacy=True to return one representative for family space subgroups related by the crystallographic parent. Set it to False only when you need every conjugate family subgroup explicitly:

all_conjugates = generator.enumerate(
    spin_only_group_type=SpinOnlyGroupType.COLLINEAR,
    k_index=1,
    max_depth=0,
    up_to_parent_conjugacy=False,
)

This option changes family-subgroup reduction. It does not disable the spin-frame equivalence applied within each retained family subgroup.

Choose the magnetic-site filter¶

By default, the generator omits family subgroups that change the multiplicity of the supplied magnetic sites. Disable this constructor-time filter only when those splittings are part of the intended search:

generator = SSAGenerator(
    prim_cell=primitive_cell,
    magnetic_site_indices=magnetic_site_indices,
    multiplicity_preserving=False,
)

Change one control at a time and record the number of returned candidates. For the exact equivalence relations and subgroup construction, see Enumeration and equivalence. For the underlying scientific derivation, see the SpinForge article.