Sketch out Spectrum API

1 files changed, 170 insertions, 0 deletions

diff --git a/libcrystfel/src/spectrum.c b/libcrystfel/src/spectrum.c
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+++ b/libcrystfel/src/spectrum.c
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+/*
+ * spectrum.c
+ *
+ * A class representing a radiation spectrum
+ *
+ * Copyright © 2019 Deutsches Elektronen-Synchrotron DESY,
+ *                  a research centre of the Helmholtz Association.
+ *
+ * Authors:
+ *   2019 Thomas White <taw@physics.org>
+ *
+ * This file is part of CrystFEL.
+ *
+ * CrystFEL is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * CrystFEL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with CrystFEL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "spectrum.h"
+#include "utils.h"
+
+
+/**
+ * \file spectrum.h
+ */
+
+
+enum spectrumrep
+{
+	SPEC_HISTOGRAM,
+	SPEC_GAUSSIANS
+};
+
+struct _spectrum
+{
+	enum spectrumrep rep;
+};
+
+
+/**
+ * Create a new \ref Spectrum.
+ *
+ * \returns The new spectrum, or NULL on failure.
+ *
+ */
+Spectrum *spectrum_new()
+{
+	Spectrum *s;
+
+	s = malloc(sizeof(Spectrum));
+	if ( s == NULL ) return NULL;
+
+	return s;
+}
+
+
+/**
+ * \param s A \ref Spectrum
+ *
+ * Frees a \ref Spectrum.
+ */
+void spectrum_free(Spectrum *s)
+{
+	free(s);
+}
+
+
+/**
+ * \param s A \ref Spectrum
+ * \param tol Fraction of spectrum required
+ *
+ * \returns The number of Gaussians needed to represent at least \p tol
+ * fraction of the total intensity in the spectrum.
+ */
+int spectrum_get_num_gaussians(Spectrum *s, double tol)
+{
+	return 0;
+}
+
+
+/**
+ * \param s A \ref Spectrum
+ * \param n The index number of the required Gaussian
+ *
+ * Returns The \p n-th Gaussian to represent the spectrum.  The Gaussians are
+ * returned in descending order of integrated intensity, indexed from zero.
+ *
+ * If \p n is greater than or equal to the number of Gaussians needed to account
+ * for 100% of the spectrum, the returned Gaussian will have zero height.
+ *
+ * \returns The \p n-th Gaussian.
+ */
+struct gaussian spectrum_get_gaussian(Spectrum *s, int n)
+{
+	struct gaussian g;
+	g.kcen = 0.0;
+	g.sigma = 0.0;
+	g.height = 0.0;
+	return g;
+}
+
+
+/**
+ * \param s A \ref Spectrum
+ * \param k A wavenumber (in 1/metres)
+ *
+ * Returns the spectral density at wavenumber \p k.
+ * To calculate the "amount of intensity" from this, you'll need to multiply
+ * the value by a small width of k.
+ *
+ * \returns The density at \p k.
+ */
+double spectrum_get_density_at_k(Spectrum *s, double k)
+{
+	return 0.0;
+}
+
+
+/**
+ * \param s A \ref Spectrum
+ * \param tol Fraction of spectrum required
+ * \param kmin Location to store minimum k value
+ * \param kmax Location to store maximum k value
+ *
+ * Returns the range of k values needed to capture \p tol of the spectrum.
+ */
+void spectrum_get_range(Spectrum *s, double tol, double *kmin, double *kmax)
+{
+}
+
+
+/**
+ * \param s A \ref Spectrum
+ * \param gs Pointer to array of \ref gaussian structures
+ * \param n_gauss Number of Gaussians in \p gs
+ *
+ * Sets the spectrum in terms of a number of Gaussians.
+ */
+void spectrum_set_gaussians(Spectrum *s, struct gaussian *gs, int n_gauss)
+{
+	/* FIXME: sort them */
+}
+
+
+/**
+ * \param s A \ref Spectrum
+ * \param kcens Pointer to array of k values in the centres of the bins
+ * \param heights Pointer to array of spectral density values
+ * \param nbins Number of bins
+ *
+ * Sets the spectrum in terms of a histogram.
+ */
+void spectrum_set_histogram(Spectrum *s, double *kcens, double *heights,
+                            int nbins)
+{
+}