tJDistributed

A block in a \(t-J\) type Hilbert space, i.e. fermions with \(\uparrow, \downarrow\) spin excluding doubly occupied sites with distributed computing capabilities.

Sources tj_distributed.hpp, tj_distributed.cpp

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Constructors

C++

tJDistributed(int64_t nsites, int64_t nup, int64_t ndn, std::string backend = "auto");

Name	Description	Default
nsites	number of sites (integer)
nup	number of "up" electrons (integer)
ndn	number of "dn" electrons (integer)
backend	backend used for coding the basis states	auto

The parameter backend chooses how the block is coded internally. By using the default parameter auto the backend is chosen automatically. Alternatives are 32bit, 64bit.

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Iteration

An tJDistributed block can be iterated over, where at each iteration a ProductState representing the corresponding basis state is returned.

C++

auto block = tJDistributed(4, 2, 1);
for (auto pstate : block) {
    Log("{} {}", to_string(pstate), index(block, pstate));
}

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Methods

index

Returns the index of a given ProductState in the basis of the tJDistributed block.

C++

int64_t index(tJDistributed const &block, ProductState const &pstate);

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nsites

Returns the number of sites of the block.

C++

int64_t nsites(tJDistributed const &block);

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size

Returns the size of the block on a local process.

C++

int64_t size(tJDistributed const &block) const;

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dim

Returns the dimension of the block, i.e. the sum of all sizes across all processes.

C++

int64_t dim(tJDistributed const &block) const;

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isreal

Returns whether the block can be used with real arithmetic. Complex arithmetic is needed when a Representation is genuinely complex.

C++

bool isreal(tJDistributed const &block);