1 files changed, 85 insertions, 0 deletions
diff --git a/src/libcf/cf_dispersion.c b/src/libcf/cf_dispersion.c
new file mode 100644
index 0000000..19a47c1
--- /dev/null
+++ b/src/libcf/cf_dispersion.c
@@ -0,0 +1,85 @@
+/*****************************************************************************
+ *              Johns Hopkins University
+ *              Center For Astrophysical Sciences
+ *              FUSE
+ *****************************************************************************
+ *
+ * Description: Assigns wavelength to each photon in data stream.  
+ *                    
+ * Returns:     0 upon successful completion.
+ *
+ * History:     05/15/06   1.1   wvd	Adapt from cf_astigmatism_and_dispersion.c
+ *					Program incorporates cf_x2lambda.
+ *
+ ****************************************************************************/
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include "calfuse.h"
+
+static char CF_PRGM_ID[] = "cf_dispersion";
+static char CF_VER_NUM[] = "1.1";
+
+
+int
+cf_dispersion(fitsfile *infits, long nevents, float *x,
+		   unsigned char *channel, float *lambda)
+{
+    char  	wave_file[FLEN_VALUE];
+    float	*wavelength=NULL;
+    float	x_lower, x_upper, weight_l, weight_u, wave_l, wave_u;
+    int	  	ap, errflg=0, nwave, xl_int, xu_int, status=0;
+    long	k;
+    fitsfile 	*wavefits;
+
+    /* Enter a timestamp into the log. */
+    cf_error_init(CF_PRGM_ID, CF_VER_NUM, stderr);
+    cf_timestamp(CF_PRGM_ID, CF_VER_NUM, "Begin Processing");
+
+    if ((errflg = cf_proc_check(infits, CF_PRGM_ID))) return errflg;
+
+    FITS_read_key(infits, TSTRING, "WAVE_CAL", wave_file, NULL, &status);
+    FITS_open_file(&wavefits, cf_cal_file(wave_file), READONLY, &status);
+
+    /* Cycle through channels, skipping #4 (pinhole) */
+    for (ap = 1; ap < 8; ap++) {
+	if (ap == 4) continue;
+
+    	FITS_movabs_hdu(wavefits, ap+1, NULL, &status);
+	nwave = cf_read_col(wavefits, TFLOAT, "WAVELENGTH", (void **) &wavelength);
+
+	/* Compute wavelength for each event by interpolation. */
+        for (k = 0; k < nevents; k++) {
+	    if (channel[k] == ap) {
+		x_lower = floor(x[k]);
+		x_upper = ceil(x[k]);
+		xl_int	= (int) (x_lower + 0.5);
+		xu_int	= (int) (x_upper + 0.5);
+		if (xl_int >= 0 && xu_int < nwave) {
+		    if (xl_int == xu_int)
+			lambda[k] = wavelength[xl_int];
+		    else {
+		        weight_l = x_upper - x[k];
+		        weight_u = x[k] - x_lower;
+		        wave_l = wavelength[xl_int];
+		        wave_u = wavelength[xu_int];
+		        lambda[k] = wave_l * weight_l + wave_u * weight_u;
+		    }
+		}
+		else
+		    channel[k] = 0;
+	    }
+	}
+        /* Space for wavelength array is allocated in each loop. */
+	free(wavelength);
+    }
+    FITS_close_file(wavefits, &status);
+
+    /* Update processing flags. */
+    cf_proc_update(infits, CF_PRGM_ID, "COMPLETE");
+    cf_timestamp(CF_PRGM_ID, CF_VER_NUM, "Done Processing");
+
+    return status;
+}