diff --git a/libsharp/sharp.c b/libsharp/sharp.c
index b5bb7b1..73d43c0 100644
--- a/libsharp/sharp.c
+++ b/libsharp/sharp.c
@@ -593,7 +593,8 @@ static void sharp_build_job_common (sharp_job *job, sharp_jobtype type,
   const sharp_geom_info *geom_info, const sharp_alm_info *alm_info, int ntrans,
   int dp, int nv)
   {
-  UTIL_ASSERT((ntrans>0),"bad number of simultaneous transforms");
+  UTIL_ASSERT((ntrans>0)&&(ntrans<=SHARP_MAXTRANS),
+    "bad number of simultaneous transforms");
   if (type==SHARP_ALM2MAP_DERIV1) spin=1;
   UTIL_ASSERT((spin>=0)&&(spin<=30), "bad spin");
   job->type = type;
diff --git a/libsharp/sharp_core.c b/libsharp/sharp_core.c
index 1d48a6f..4a932a0 100644
--- a/libsharp/sharp_core.c
+++ b/libsharp/sharp_core.c
@@ -41,6 +41,7 @@
 
 typedef complex double dcmplx;
 
+// must be in the range [0;6]
 #define MAXJOB_SPECIAL 2
 
 #define XCONCAT2(a,b) a##_##b
@@ -81,7 +82,7 @@ void inner_loop (sharp_job *job, const int *ispair,const double *cth,
     {
     switch (njobs*16+job->nv)
       {
-#if (MAXJOB_SPECIAL>=1)
+#if ((MAXJOB_SPECIAL>=1)&&(SHARP_MAXTRANS>=1))
       case 0x11:
         CONCAT3(inner_loop,1,1) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
@@ -101,7 +102,7 @@ void inner_loop (sharp_job *job, const int *ispair,const double *cth,
         CONCAT3(inner_loop,6,1) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
 #endif
-#if (MAXJOB_SPECIAL>=2)
+#if ((MAXJOB_SPECIAL>=2)&&(SHARP_MAXTRANS>=2))
       case 0x21:
         CONCAT3(inner_loop,1,2) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
@@ -121,7 +122,7 @@ void inner_loop (sharp_job *job, const int *ispair,const double *cth,
         CONCAT3(inner_loop,6,2) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
 #endif
-#if (MAXJOB_SPECIAL>=3)
+#if ((MAXJOB_SPECIAL>=3)&&(SHARP_MAXTRANS>=3))
       case 0x31:
         CONCAT3(inner_loop,1,3) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
@@ -141,7 +142,7 @@ void inner_loop (sharp_job *job, const int *ispair,const double *cth,
         CONCAT3(inner_loop,6,3) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
 #endif
-#if (MAXJOB_SPECIAL>=4)
+#if ((MAXJOB_SPECIAL>=4)&&(SHARP_MAXTRANS>=4))
       case 0x41:
         CONCAT3(inner_loop,1,4) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
@@ -161,7 +162,7 @@ void inner_loop (sharp_job *job, const int *ispair,const double *cth,
         CONCAT3(inner_loop,6,4) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
 #endif
-#if (MAXJOB_SPECIAL>=5)
+#if ((MAXJOB_SPECIAL>=5)&&(SHARP_MAXTRANS>=5))
       case 0x51:
         CONCAT3(inner_loop,1,5) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
@@ -181,7 +182,7 @@ void inner_loop (sharp_job *job, const int *ispair,const double *cth,
         CONCAT3(inner_loop,6,5) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
 #endif
-#if (MAXJOB_SPECIAL>=6)
+#if ((MAXJOB_SPECIAL>=6)&&(SHARP_MAXTRANS>=6))
       case 0x61:
         CONCAT3(inner_loop,1,6) (job, ispair,cth,sth,llim,ulim,gen,mi,idx);
         return;
@@ -203,7 +204,7 @@ void inner_loop (sharp_job *job, const int *ispair,const double *cth,
 #endif
       }
     }
-#if (MAXJOB_SPECIAL<6)
+#if (SHARP_MAXTRANS>MAXJOB_SPECIAL)
   else
     {
     switch (job->nv)
diff --git a/libsharp/sharp_inchelper1.inc.c b/libsharp/sharp_inchelper1.inc.c
index 74de2ee..9357fb2 100644
--- a/libsharp/sharp_inchelper1.inc.c
+++ b/libsharp/sharp_inchelper1.inc.c
@@ -1,11 +1,12 @@
 #define Tb CONCAT2(Tb,nvec)
 #define Y(arg) CONCAT2(arg,nvec)
 #include "sharp_core_inc.c"
-#if (MAXJOB_SPECIAL<6)
+
+#if (SHARP_MAXTRANS>MAXJOB_SPECIAL)
 #include "sharp_core_inc3.c"
 #endif
 
-#if (MAXJOB_SPECIAL>=1)
+#if ((MAXJOB_SPECIAL>=1)&&(SHARP_MAXTRANS>=1))
 #define njobs 1
 #define Z(arg) CONCAT3(arg,nvec,njobs)
 #include "sharp_core_inc2.c"
@@ -13,7 +14,7 @@
 #undef njobs
 #endif
 
-#if (MAXJOB_SPECIAL>=2)
+#if ((MAXJOB_SPECIAL>=2)&&(SHARP_MAXTRANS>=2))
 #define njobs 2
 #define Z(arg) CONCAT3(arg,nvec,njobs)
 #include "sharp_core_inc2.c"
@@ -21,7 +22,7 @@
 #undef njobs
 #endif
 
-#if (MAXJOB_SPECIAL>=3)
+#if ((MAXJOB_SPECIAL>=3)&&(SHARP_MAXTRANS>=3))
 #define njobs 3
 #define Z(arg) CONCAT3(arg,nvec,njobs)
 #include "sharp_core_inc2.c"
@@ -29,7 +30,7 @@
 #undef njobs
 #endif
 
-#if (MAXJOB_SPECIAL>=4)
+#if ((MAXJOB_SPECIAL>=4)&&(SHARP_MAXTRANS>=4))
 #define njobs 4
 #define Z(arg) CONCAT3(arg,nvec,njobs)
 #include "sharp_core_inc2.c"
@@ -37,7 +38,7 @@
 #undef njobs
 #endif
 
-#if (MAXJOB_SPECIAL>=5)
+#if ((MAXJOB_SPECIAL>=5)&&(SHARP_MAXTRANS>=5))
 #define njobs 5
 #define Z(arg) CONCAT3(arg,nvec,njobs)
 #include "sharp_core_inc2.c"
@@ -45,7 +46,7 @@
 #undef njobs
 #endif
 
-#if (MAXJOB_SPECIAL>=6)
+#if ((MAXJOB_SPECIAL>=6)&&(SHARP_MAXTRANS>=6))
 #define njobs 6
 #define Z(arg) CONCAT3(arg,nvec,njobs)
 #include "sharp_core_inc2.c"
diff --git a/libsharp/sharp_internal.h b/libsharp/sharp_internal.h
index 1a05256..d573be9 100644
--- a/libsharp/sharp_internal.h
+++ b/libsharp/sharp_internal.h
@@ -38,6 +38,8 @@
 
 #include "sharp.h"
 
+#define SHARP_MAXTRANS 10
+
 typedef enum { FLOAT, DOUBLE } sharp_fde;
 
 typedef struct