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* Documentation * Improved qp_set_frozen_core * Changed all ishft * New install script OK * Variable level shift in HF
69 lines
2.5 KiB
ReStructuredText
69 lines
2.5 KiB
ReStructuredText
========
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The |qp|
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========
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.. image:: /_static/qp.png
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:align: center
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:width: 200px
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:alt: Quantum Package
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What it is
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==========
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The |qp| is an open-source programming environment for quantum chemistry,
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especially for `wave function methods <https://en.wikipedia.org/wiki/Ab_initio_quantum_chemistry_methods>`_.
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The main goal is the development of selected configuration interaction (sCI)
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methods and multi-reference perturbation theory (MR-PT) in the
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determinant-driven paradigm. The determinant-driven framework allows the
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programmer to include any arbitrary set of determinants in the variational
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space, and thus gives a complete freedom in the methodological development. All
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the programs are developed with the `IRPF90`_ code generator, which simplifies
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the collaborative development, and the development of new features.
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What it is not
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==============
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The |qp| is *not* a general purpose quantum chemistry program.
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First of all, it is a library. The users of the |qp| should develop
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their own programs.
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The |qp| has been designed specifically for sCI, so all the
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algorithms which are programmed are not adapted to run SCF or DFT calculations
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on thousands of atoms. Currently, the systems targeted have less than 600
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molecular orbitals.
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The |qp| is *not* a massive production code. For conventional
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methods such as Hartree-Fock, CISD or MP2, the users are recommended to use the
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existing standard production codes which are designed to make these methods run
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fast. Again, the role of the |qp| is to make life simple for the
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developer. Once a new method is developed and tested, the developer is encouraged
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to consider re-expressing it with an integral-driven formulation, and to
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implement the new method in open-source production codes, such as `NWChem`_
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or |GAMESS|.
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A few examples of applications
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==============================
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Multiple programs were developed with the |qp|, such as:
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- Selected Full-CI + Epstein-Nesbet PT2 (CIPSI) :cite:`Caffarel_2016,Caffarel_2016.2,Loos_2018,Scemama_2018,Dash_2018`
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- Hybrid stochastic/deterministic MR-PT2 :cite:`Garniron_2017.2,Loos_2018`
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- CIS, CISD, MP2
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- Selected CISD
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- Jeziorsky-Monkhorst MR-PT2 :cite:`Giner_2017`
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- Selected CAS+SD
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- Selected difference-dedicated CI (DD-CI)
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- Multi-Reference Coupled Cluster (MR-CCSD) :cite:`Giner_2016,Garniron_2017`
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- Shifted-Bk with CIPSI :cite:`Garniron_2018`
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- CIPSI with range-separated DFT
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All these programs can generate ground and excited states, and spin pure wave
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functions (eigenstates of |S^2|).
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