add: density noise backend

1 files changed, 57 insertions, 0 deletions

diff --git a/include/core/noise.h b/include/core/noise.h
new file mode 100644
index 0000000..6232d8e
--- /dev/null
+++ b/include/core/noise.h
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "maths/complex.h"
+#include "maths/matrix.h"
+
+struct PsiKrausOperator
+{
+	struct PsiMatrix matrix;
+	const char *name;
+};
+
+struct PsiKrausOperator psi_new_kraus_operator(const char *name, struct PsiMatrix matrix);
+void psi_free_kraus_operator(struct PsiKrausOperator *op);
+
+struct PsiNoiseChannel
+{
+	const char *name;
+	struct PsiKrausOperator *operators;
+	size_t operator_count;
+	size_t num_qubits;
+};
+
+struct PsiNoiseChannel psi_new_noise_channel(const char *name, const struct PsiKrausOperator *operators, size_t count, size_t num_qubits);
+void psi_free_noise_channel(struct PsiNoiseChannel *channel);
+
+struct PsiNoiseChannel psi_depolarising_channel(double p);
+struct PsiNoiseChannel psi_amplitude_damping_channel(double gamma);
+struct PsiNoiseChannel psi_phase_damping_channel(double gamma);
+struct PsiNoiseChannel psi_bit_flip_channel(double p);
+struct PsiNoiseChannel psi_phase_flip_channel(double p);
+struct PsiNoiseChannel psi_bit_phase_flip_channel(double p);
+struct PsiNoiseChannel psi_generalised_amplitude_damping_channel(double p, double gamma);
+
+struct PsiDensityMatrix
+{
+	struct PsiComplex *data;
+	size_t dim;
+	size_t num_qubits;
+};
+
+struct PsiDensityMatrix psi_new_density_matrix(size_t num_qubits);
+struct PsiDensityMatrix psi_new_density_matrix_from_state(const struct PsiComplex *state, size_t len);
+void psi_free_density_matrix(struct PsiDensityMatrix *dm);
+
+struct PsiComplex psi_get_density_matrix(struct PsiDensityMatrix dm, size_t row, size_t col);
+void psi_set_density_matrix(struct PsiDensityMatrix *dm, size_t row, size_t col, struct PsiComplex value);
+struct PsiComplex psi_trace_density_matrix(struct PsiDensityMatrix dm);
+double psi_purity_density_matrix(struct PsiDensityMatrix dm);
+bool psi_is_pure_density_matrix(struct PsiDensityMatrix dm, double tolerance);
+void psi_density_matrix_probabilities(struct PsiDensityMatrix dm, double *out);
+void psi_apply_unitary_density_matrix(struct PsiDensityMatrix *dm, struct PsiMatrix gate, const size_t *targets, size_t target_count);
+void psi_apply_noise_channel(struct PsiDensityMatrix *dm, struct PsiNoiseChannel channel, size_t target);
+double psi_measure_probability_density_matrix(struct PsiDensityMatrix dm, size_t qubit, size_t outcome);
+double psi_fidelity_density_matrix(struct PsiDensityMatrix dm, const struct PsiComplex *state);