From a3efcb98a5c165307cc28749e26bffc12ebbf245 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@bitwiz.org.uk>
Date: Tue, 13 Oct 2009 19:02:20 +0200
Subject: Image, feature and unit cell infrastructure

Brought across from DTR and Synth3D
---
 src/cell.c | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 src/cell.c

(limited to 'src/cell.c')

diff --git a/src/cell.c b/src/cell.c
new file mode 100644
index 00000000..d2495b0f
--- /dev/null
+++ b/src/cell.c
@@ -0,0 +1,148 @@
+/*
+ * cell.c
+ *
+ * Unit Cell Calculations
+ *
+ * (c) 2007-2009 Thomas White <thomas.white@desy.de>
+ *
+ * template_index - Indexing diffraction patterns by template matching
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <math.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "cell.h"
+#include "utils.h"
+
+
+/* Update the cartesian representation from the crystallographic one */
+static void cell_update_cartesian(UnitCell *cell)
+{
+	double tmp, V, cosalphastar, cstar;
+
+	if ( !cell ) return;
+
+	/* a in terms of x, y and z
+	 * +a (cryst) is defined to lie along +x (cart) */
+	cell->ax = cell->a;
+	cell->ay = 0.0;
+	cell->az = 0.0;
+
+	/* b in terms of x, y and z
+	 * b (cryst) is defined to lie in the xy (cart) plane */
+	cell->bx = cell->b*cos(cell->gamma);
+	cell->by = cell->b*sin(cell->gamma);
+	cell->bz = 0.0;
+
+	tmp = cos(cell->alpha)*cos(cell->alpha)
+		- cos(cell->beta)*cos(cell->beta)
+		- cos(cell->gamma)*cos(cell->gamma)
+		+ 2.0*cos(cell->alpha)*cos(cell->beta)*cos(cell->gamma);
+	V = cell->a * cell->b * cell->c * sqrt(1.0 - tmp);
+
+	cosalphastar = cos(cell->beta)*cos(cell->gamma) - cos(cell->alpha);
+	cosalphastar /= sin(cell->beta)*sin(cell->gamma);
+
+	cstar = (cell->a * cell->b * sin(cell->gamma))/V;
+
+	/* c in terms of x, y and z */
+	cell->cx = cell->c*cos(cell->beta);
+	cell->cy = -cell->c*sin(cell->beta)*cosalphastar;
+	cell->cz = 1.0/cstar;
+}
+
+
+/* Update the crystallographic representation from the cartesian one */
+static void cell_update_crystallographic(UnitCell *cell)
+{
+	if ( !cell ) return;
+
+	cell->a = modulus(cell->ax, cell->ay, cell->az);
+	cell->b = modulus(cell->bx, cell->by, cell->bz);
+	cell->c = modulus(cell->cx, cell->cy, cell->cz);
+
+	cell->alpha = angle_between(cell->bx, cell->by, cell->bz,
+					cell->cx, cell->cy, cell->cz);
+	cell->beta = angle_between(cell->ax, cell->ay, cell->az,
+					cell->cx, cell->cy, cell->cz);
+	cell->gamma = angle_between(cell->ax, cell->ay, cell->az,
+					cell->bx, cell->by, cell->bz);
+
+	printf("a=%f nm\n", cell->a);
+	printf("b=%f nm\n", cell->b);
+	printf("c=%f nm\n", cell->c);
+	printf("alpha = %f deg\n", rad2deg(cell->alpha));
+	printf(" beta = %f deg\n", rad2deg(cell->beta));
+	printf("gamma = %f deg\n", rad2deg(cell->gamma));
+}
+
+
+UnitCell *cell_new()
+{
+	UnitCell *cell;
+
+	cell = malloc(sizeof(UnitCell));
+	if ( !cell ) return NULL;
+
+	cell->a = 1.0;
+	cell->b = 1.0;
+	cell->c = 1.0;
+	cell->alpha = M_PI_2;
+	cell->beta = M_PI_2;
+	cell->gamma = M_PI_2;
+
+	cell_update_cartesian(cell);
+
+	return cell;
+}
+
+
+void cell_set_parameters(UnitCell *cell, double a, double b, double c,
+				double alpha, double beta, double gamma)
+{
+	if ( !cell ) return;
+
+	cell->a = a;
+	cell->b = b;
+	cell->c = c;
+	cell->alpha = alpha;
+	cell->beta = beta;
+	cell->gamma = gamma;
+
+	cell_update_cartesian(cell);
+}
+
+
+void cell_set_cartesian(UnitCell *cell,
+			double ax, double ay, double az,
+			double bx, double by, double bz,
+			double cx, double cy, double cz)
+{
+	if ( !cell ) return;
+
+	cell->ax = ax;  cell->ay = ay;  cell->az = az;
+	cell->bx = bx;  cell->by = by;  cell->bz = bz;
+	cell->cx = cx;  cell->cy = cy;  cell->cz = cz;
+
+	cell_update_crystallographic(cell);
+}
+
+
+UnitCell *cell_new_from_parameters(double a, double b, double c,
+				double alpha, double beta, double gamma)
+{
+	UnitCell *cell;
+
+	cell = cell_new();
+	if ( !cell ) return NULL;
+
+	cell_set_parameters(cell, a, b, c, alpha, beta, gamma);
+
+	return cell;
+}
-- 
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