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8f89e3d239
* Documentation * Improved qp_set_frozen_core * Changed all ishft * New install script OK * Variable level shift in HF
36 lines
787 B
ReStructuredText
36 lines
787 B
ReStructuredText
.. _bitmask:
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.. program:: bitmask
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.. default-role:: option
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==============
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Bitmask Module
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==============
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The central part of this module is the :file:`bitmasks_module.f90` file. It contains
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the constants that will be used to define on which kind of integer the bitmasks
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will be defined.
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In the program, to represent a determinant as a pair of bitstrings,
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the determinant should be defined as
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.. code-block:: fortran
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use bitmasks
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integer(bit_kind) :: determinant(N_int,2)
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:file:`bitmasks_routines.irp.f` contains helper routines to manipulate bitmask, like
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transforming a bit string to a list of integers for example.
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`bit_kind_shift`, `bit_kind_size` and `bit_kind` are supposed to be consistent::
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2**bit_kind_shift = bit_kind_size
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bit_kind = bit_kind_size / 8
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