diff --git a/libsharp/sharp.c b/libsharp/sharp.c
index d833516..b5bb7b1 100644
--- a/libsharp/sharp.c
+++ b/libsharp/sharp.c
@@ -43,9 +43,10 @@
 typedef complex double dcmplx;
 typedef complex float  fcmplx;
 
+static int chunksize_min=500, nchunks_max=10;
+
 static void get_chunk_info (int ndata, int nmult, int *nchunks, int *chunksize)
   {
-  static const int chunksize_min=500, nchunks_max=10;
   *chunksize = IMAX(chunksize_min,(ndata+nchunks_max-1)/nchunks_max);
   *chunksize = ((*chunksize+nmult-1)/nmult)*nmult;
   *nchunks = (ndata+*chunksize-1) / *chunksize;
@@ -625,6 +626,11 @@ void sharp_execute (sharp_jobtype type, int spin, int add_output, void *alm,
   if (opcnt!=NULL) *opcnt = job.opcnt;
   }
 
+void sharp_set_chunksize_min(int new_chunksize_min)
+  { chunksize_min=new_chunksize_min; }
+void sharp_set_nchunks_max(int new_nchunks_max)
+  { nchunks_max=new_nchunks_max; }
+
 int sharp_get_nv_max (void)
 { return 6; }
 
diff --git a/libsharp/sharp_lowlevel.h b/libsharp/sharp_lowlevel.h
index 96dca06..70821ae 100644
--- a/libsharp/sharp_lowlevel.h
+++ b/libsharp/sharp_lowlevel.h
@@ -179,6 +179,9 @@ void sharp_execute (sharp_jobtype type, int spin, int add_output, void *alm,
   void *map, const sharp_geom_info *geom_info, const sharp_alm_info *alm_info,
   int ntrans, int dp, int nv, double *time, unsigned long long *opcnt);
 
+void sharp_set_chunksize_min(int new_chunksize_min);
+void sharp_set_nchunks_max(int new_nchunks_max);
+
 /*! \} */
 
 #ifdef __cplusplus