AlphaSGrid

struct AlphaSGrid

A strong-coupling grid in the LHAPDF format, loaded from a file.

Holds the \(\alpha_s(q)\) knots of an LHAPDF .info set; RunningCoupling does the interpolation.

Public Functions

AlphaSGrid(const std::string &file)

Load an LHAPDF-format alpha_s grid.

Parameters:

file – Path to the grid file.

std::size_t q_count() const

Number of scale knots.

void initialize_coefficients(Tensor tensor) const

Fill tensor with the interpolation coefficients.

void initialize_logq2(Tensor tensor) const

Fill tensor with the log(q^2) knots.

std::vector<std::size_t> coefficients_shape(bool batch_dim = false) const

Shape of the coefficient tensor, optionally with a leading batch axis.

std::vector<std::size_t> logq2_shape(bool batch_dim = false) const

Shape of the log(q^2) tensor.

void initialize_globals(ContextPtr context, const std::string &prefix = "") const

Upload the grid to context as compute-graph globals under prefix.

Public Members

std::vector<double> q

Scale grid knots.

std::vector<double> logq2

log(q^2) grid knots.

std::vector<double> values

alpha_s values at the knots.

std::vector<std::size_t> region_sizes

Knot counts of the sub-grid regions.