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Tensors

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Batching Oscillation calculations

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Not really properly working at the moment :)

Denton-Parke Propagator

The Denton-Parke (DP) propagator is an implementation of the nufast algorithm using tensors to allow it to be automatically differentiated. It is implemented in the DPpropagator class. This propagator is less flexible than the general Propagator class: It can only be used to calculate 3 flavour oscillations in the usual PMNS parameterisation. However what it lacks in flexibility it makes up for in speed. It leverages the Eigenvector-eigenvalue identity to very quickly calculate the effective PMNS matrix in the presence of matter.

It’s use is slightly different to the usual Propagator, as it requires no additional matter solver to be provided.

A basic usage example looks like

C++Python

// set up tensors for the oscillation parameters and energies
Tensor theta23 = Tensor::zeros({1}, dtypes::kComplexFloat, dtypes::kCPU, false);
Tensor theta13 = Tensor::zeros({1}, dtypes::kComplexFloat, dtypes::kCPU, false);
Tensor theta12 = Tensor::zeros({1}, dtypes::kComplexFloat, dtypes::kCPU, false);
Tensor deltaCP = Tensor::zeros({1}, dtypes::kComplexFloat, dtypes::kCPU, false);
Tensor dmsq21 = Tensor::zeros({1}, dtypes::kComplexFloat, dtypes::kCPU, false);
Tensor dmsq31 = Tensor::zeros({1}, dtypes::kComplexFloat, dtypes::kCPU, false);

Tensor energies = Tensor::ones({1, 1}, dtypes::kComplexFloat).requiresGrad(false).hasBatchDim(true);

// instantiate the propagator
DPpropagator dpPropagator = DPpropagator(baseline, false, density, 10);

// link parameters to the propagator
dpPropagator.setEnergies(energies);
dpPropagator.setParameters(theta12, theta23, theta13, deltaCP, dmsq21, dmsq31);

// set values of the parameters
theta23.setValue({0}, 0.4 * M_PI);
theta13.setValue({0}, 0.3 * M_PI);
theta12.setValue({0}, 0.2 * M_PI);

dmsq21.setValue({0}, m1 * m1 - m2 * m2);
dmsq31.setValue({0}, m1 * m1 - m3 * m3);

deltaCP.setValue({0}, dcp);

// calculate probabilities
Tensor dpProbabilities = dpPropagator.calculateProbs();