add get_avg_index_{d2o,h2o} functions

1 files changed, 5 insertions, 6 deletions

diff --git a/src/optics.h b/src/optics.h
index 0e7740b..26e268e 100644
--- a/src/optics.h
+++ b/src/optics.h
@@ -23,16 +23,15 @@
 /* Global error string when optics_init() returns -1. */
 extern char optics_err[256];
 
-/* Index of refraction in water and heavy water averaged over the Cerenkov
- * spectrum and the PMT quantum efficiency.
- *
- * Note: You must call optics_init() before using these! */
-extern double avg_index_h2o, avg_index_d2o;
-
 /* Initialize the optics data by precomputing the average absorption and
  * scattering tables. */
 int optics_init(void);
 
+/* Functions to get the index of refraction in water and heavy water averaged
+ * over the Cerenkov spectrum and the PMT quantum efficiency. */
+double get_avg_index_d2o(void);
+double get_avg_index_h2o(void);
+
 /* Functions for computing the index of refraction. */
 double get_index(double p, double wavelength, double T);
 double get_index_snoman_h2o(double wavelength);