pattern_sim: Add --flat

6 files changed, 32 insertions, 23 deletions

diff --git a/src/diffraction-gpu.c b/src/diffraction-gpu.c
index 22abcfd2..ea50b3fa 100644
--- a/src/diffraction-gpu.c
+++ b/src/diffraction-gpu.c
@@ -72,7 +72,8 @@ struct gpu_context
 };
 
 
-static void check_sinc_lut(struct gpu_context *gctx, int n, int no_fringes)
+static void check_sinc_lut(struct gpu_context *gctx, int n,
+                           int no_fringes, int flat)
 {
 	cl_int err;
 	cl_image_format fmt;
@@ -105,8 +106,10 @@ static void check_sinc_lut(struct gpu_context *gctx, int n, int no_fringes)
 		for ( i=1; i<SINC_LUT_ELEMENTS; i++ ) {
 			double x, val;
 			x = (double)i/SINC_LUT_ELEMENTS;
-			if ( no_fringes && (x > 1.0/n) && (1.0-x > 1.0/n) ) {
+			if ( (flat || no_fringes) && (x > 1.0/n) && (1.0-x > 1.0/n) ) {
 				val = 0.0;
+			} else if ( flat ) {
+				val = n;
 			} else {
 				val = fabs(sin(M_PI*n*x)/sin(M_PI*x));
 			}
@@ -279,7 +282,7 @@ static int do_panels(struct gpu_context *gctx, struct image *image,
 
 int get_diffraction_gpu(struct gpu_context *gctx, struct image *image,
                         int na, int nb, int nc, UnitCell *ucell,
-                        int no_fringes)
+                        int no_fringes, int flat)
 {
 	double ax, ay, az;
 	double bx, by, bz;
@@ -297,9 +300,9 @@ int get_diffraction_gpu(struct gpu_context *gctx, struct image *image,
 	}
 
 	/* Ensure all required LUTs are available */
-	check_sinc_lut(gctx, na, no_fringes);
-	check_sinc_lut(gctx, nb, no_fringes);
-	check_sinc_lut(gctx, nc, no_fringes);
+	check_sinc_lut(gctx, na, no_fringes, flat);
+	check_sinc_lut(gctx, nb, no_fringes, flat);
+	check_sinc_lut(gctx, nc, no_fringes, flat);
 
 	/* Unit cell */
 	cell_get_cartesian(ucell, &ax, &ay, &az, &bx, &by, &bz, &cx, &cy, &cz);
diff --git a/src/diffraction-gpu.h b/src/diffraction-gpu.h
index c313859f..0b0e364b 100644
--- a/src/diffraction-gpu.h
+++ b/src/diffraction-gpu.h
@@ -3,11 +3,11 @@
  *
  * Calculate diffraction patterns by Fourier methods (GPU version)
  *
- * Copyright © 2012-2014 Deutsches Elektronen-Synchrotron DESY,
+ * Copyright © 2012-2017 Deutsches Elektronen-Synchrotron DESY,
  *                       a research centre of the Helmholtz Association.
  *
  * Authors:
- *   2010-2014 Thomas White <taw@physics.org>
+ *   2010-2017 Thomas White <taw@physics.org>
  *
  * This file is part of CrystFEL.
  *
@@ -42,7 +42,7 @@ struct gpu_context;
 
 extern int get_diffraction_gpu(struct gpu_context *gctx, struct image *image,
                                int na, int nb, int nc, UnitCell *ucell,
-                               int no_fringes);
+                               int no_fringes, int flat);
 extern struct gpu_context *setup_gpu(int no_sfac,
                                      const double *intensities,
                                      const unsigned char *flags,
@@ -53,7 +53,7 @@ extern void cleanup_gpu(struct gpu_context *gctx);
 
 static int get_diffraction_gpu(struct gpu_context *gctx, struct image *image,
                                int na, int nb, int nc, UnitCell *ucell,
-                               int no_fringes)
+                               int no_fringes, int flat)
 {
 	/* Do nothing */
 	ERROR("This copy of CrystFEL was not compiled with OpenCL support.\n");
diff --git a/src/diffraction.c b/src/diffraction.c
index 93674f52..4cceba0e 100644
--- a/src/diffraction.c
+++ b/src/diffraction.c
@@ -48,7 +48,7 @@
 #define SINC_LUT_ELEMENTS (4096)
 
 
-static double *get_sinc_lut(int n, int no_fringes)
+static double *get_sinc_lut(int n, int no_fringes, int flat)
 {
 	int i;
 	double *lut;
@@ -63,8 +63,10 @@ static double *get_sinc_lut(int n, int no_fringes)
 		for ( i=1; i<SINC_LUT_ELEMENTS; i++ ) {
 			double x, val;
 			x = (double)i/SINC_LUT_ELEMENTS;
-			if ( no_fringes && (x > 1.0/n) && (1.0-x > 1.0/n) ) {
+			if ( (flat || no_fringes) && (x > 1.0/n) && (1.0-x > 1.0/n) ) {
 				val = 0.0;
+			} else if ( flat ) {
+				val = n;
 			} else {
 				val = fabs(sin(M_PI*n*x)/sin(M_PI*x));
 			}
@@ -716,7 +718,8 @@ struct sample *generate_twocolour(struct image *image)
 void get_diffraction(struct image *image, int na, int nb, int nc,
                      const double *intensities, const double *phases,
                      const unsigned char *flags, UnitCell *cell,
-                     GradientMethod m, const SymOpList *sym, int no_fringes)
+                     GradientMethod m, const SymOpList *sym,
+                     int no_fringes, int flat)
 {
 	double ax, ay, az;
 	double bx, by, bz;
@@ -728,9 +731,9 @@ void get_diffraction(struct image *image, int na, int nb, int nc,
 
 	cell_get_cartesian(cell, &ax, &ay, &az, &bx, &by, &bz, &cx, &cy, &cz);
 
-	lut_a = get_sinc_lut(na, no_fringes);
-	lut_b = get_sinc_lut(nb, no_fringes);
-	lut_c = get_sinc_lut(nc, no_fringes);
+	lut_a = get_sinc_lut(na, no_fringes, flat);
+	lut_b = get_sinc_lut(nb, no_fringes, flat);
+	lut_c = get_sinc_lut(nc, no_fringes, flat);
 
 	for ( i=0; i<image->nsamples; i++ ) {
 
diff --git a/src/diffraction.h b/src/diffraction.h
index 28f3ec0a..ca4e3bde 100644
--- a/src/diffraction.h
+++ b/src/diffraction.h
@@ -52,7 +52,7 @@ extern void get_diffraction(struct image *image, int na, int nb, int nc,
                             const double *intensities, const double *phases,
                             const unsigned char *flags, UnitCell *cell,
                             GradientMethod m, const SymOpList *sym,
-                            int no_fringes);
+                            int no_fringes, int flat);
 
 extern struct sample *generate_tophat(struct image *image);
 
diff --git a/src/pattern_sim.c b/src/pattern_sim.c
index a3fea8e3..52ed6d48 100644
--- a/src/pattern_sim.c
+++ b/src/pattern_sim.c
@@ -3,11 +3,11 @@
  *
  * Simulate diffraction patterns from small crystals
  *
- * Copyright © 2012-2016 Deutsches Elektronen-Synchrotron DESY,
+ * Copyright © 2012-2017 Deutsches Elektronen-Synchrotron DESY,
  *                       a research centre of the Helmholtz Association.
  *
  * Authors:
- *   2009-2016 Thomas White <taw@physics.org>
+ *   2009-2017 Thomas White <taw@physics.org>
  *   2013-2014 Chun Hong Yoon <chun.hong.yoon@desy.de>
  *   2014      Valerio Mariani
  *   2013      Alexandra Tolstikova
@@ -95,6 +95,7 @@ static void show_help(const char *s)
 "     --background=<N>      Add N photons of Poisson background (default 0).\n"
 "     --template=<file>     Take orientations from stream <file>.\n"
 "     --no-fringes          Exclude the side maxima of Bragg peaks.\n"
+"     --flat                Make Bragg peaks flat.\n"
 "     --beam-bandwidth      Beam bandwidth as a fraction. Default 1%%.\n"
 "     --photon-energy       Photon energy in eV.  Default 9000.\n"
 "     --nphotons            Number of photons per X-ray pulse.  Default 1e12.\n"
@@ -388,6 +389,7 @@ int main(int argc, char *argv[])
 	char *template_file = NULL;
 	Stream *st = NULL;
 	int no_fringes = 0;
+	int flat = 0;
 	double nphotons = 1e12;
 	double beam_radius = 1e-6;  /* metres */
 	double bandwidth = 0.01;
@@ -417,6 +419,7 @@ int main(int argc, char *argv[])
 		{"spectrum",           1, NULL,               'x'},
 		{"really-random",      0, &config_random,      1},
 		{"no-fringes",         0, &no_fringes,         1},
+		{"flat",               0, &flat,               1},
 
 		{"gpu-dev",            1, NULL,                2},
 		{"min-size",           1, NULL,                3},
@@ -990,11 +993,11 @@ int main(int argc, char *argv[])
 				                 gpu_dev);
 			}
 			err = get_diffraction_gpu(gctx, &image, na, nb, nc,
-			                          cell, no_fringes);
+			                          cell, no_fringes, flat);
 
 		} else {
 			get_diffraction(&image, na, nb, nc, intensities, phases,
-			                flags, cell, grad, sym, no_fringes);
+			                flags, cell, grad, sym, no_fringes, flat);
 		}
 		if ( err ) {
 			ERROR("Diffraction calculation failed.\n");
diff --git a/tests/gpu_sim_check.c b/tests/gpu_sim_check.c
index ba51b8db..8c666775 100644
--- a/tests/gpu_sim_check.c
+++ b/tests/gpu_sim_check.c
@@ -171,7 +171,7 @@ int main(int argc, char *argv[])
 	gpu_image.spectrum = generate_tophat(&gpu_image);
 
 	start = get_hires_seconds();
-	if ( get_diffraction_gpu(gctx, &gpu_image, 8, 8, 8, cell, 1) ) {
+	if ( get_diffraction_gpu(gctx, &gpu_image, 8, 8, 8, cell, 0, 0) ) {
 		return 1;
 	}
 	end = get_hires_seconds();
@@ -195,7 +195,7 @@ int main(int argc, char *argv[])
 
 	start = get_hires_seconds();
 	get_diffraction(&cpu_image, 8, 8, 8, NULL, NULL, NULL, cell,
-	                GRADIENT_MOSAIC, sym, 1);
+	                GRADIENT_MOSAIC, sym, 0, 0);
 	end = get_hires_seconds();
 	cpu_time = end - start;