diff --git a/qpms/qpms_c.pyx b/qpms/qpms_c.pyx
index ec88dbe..47d3b52 100644
--- a/qpms/qpms_c.pyx
+++ b/qpms/qpms_c.pyx
@@ -622,7 +622,7 @@ cdef class _ScatteringSystemAtOmega:
     cdef qpms_scatsys_at_omega_t *rawpointer(self):
         return self.ssw
 
-    def scatter_solver(self, double k, iri=None):
+    def scatter_solver(self, iri=None):
         self.check()
         return ScatteringMatrix(self, iri)
 
@@ -637,7 +637,7 @@ cdef class _ScatteringSystemAtOmega:
 
     def modeproblem_matrix_full(self):
         self.check()
-        cdef size_t flen = self.s[0].fecv_size
+        cdef size_t flen = self.ss_pyref.s[0].fecv_size
         cdef np.ndarray[np.complex_t, ndim=2] target = np.empty(
                 (flen,flen),dtype=complex, order='C')
         cdef cdouble[:,::1] target_view = target
diff --git a/qpms/scatsystem.c b/qpms/scatsystem.c
index de1b6d0..b6b1149 100644
--- a/qpms/scatsystem.c
+++ b/qpms/scatsystem.c
@@ -1675,7 +1675,7 @@ complex double *qpms_scatsys_build_translation_matrix_e_irrep_packed(
   pthread_mutex_t opistartR_mutex;
   QPMS_ENSURE_SUCCESS(pthread_mutex_init(&opistartR_mutex, NULL));
   const struct qpms_scatsys_build_translation_matrix_e_irrep_packed_parallelR_thread_arg
-    arg = {ss, &opistartR, &opistartR_mutex, iri, target_packed, J};
+    arg = {ss, &opistartR, &opistartR_mutex, iri, target_packed, k, J};
 
   // FIXME THIS IS NOT PORTABLE:
   long nthreads;