diff --git a/qpms/scatsys_translation_booster.c b/qpms/scatsys_translation_booster.c
new file mode 100644
index 0000000..5a49429
--- /dev/null
+++ b/qpms/scatsys_translation_booster.c
@@ -0,0 +1,38 @@
+#include "scatsystem.h"
+
+#define SQ(x) ((x)*(x))
+
+typedef size_t ppid_t;
+typedef size_t uoppid_t;
+
+// Unordered pair ID. TODO get rid of redundancies
+static inline uoppid_t uopairid(qpms_ss_pi_t pn_total, qpms_ss_pi_t p1, qpms_ss_pi_t p2) {
+  return pn_total * p1 + p2;
+}
+
+// Unordered pair ID count. TODO get rid of redundancies.
+static inline uoppid_t uopairarr_len(qpms_ss_pi_t pn_total) {
+  return SQ(pn_total);
+}
+
+// Ordered pair ID.
+static inline uoppid_t pairid(qpms_ss_pi_t pn_total, qpms_ss_pi_t p1, qpms_ss_pi_t p2) {
+  return pn_total * p1 + p2;
+}
+
+// Ordered pair ID count.
+static inline uoppid_t pairarr_len(qpms_ss_pi_t pn_total) {
+  return SQ(pn_total);
+}
+
+typedef struct qpms_scatsys_translation_booster {
+    double *r; // Unique distances array, indices are ppid_t
+    ppid_t *r_map; // FIXME
+} qpms_scatsys_translation_booster_t;
+
+struct qpms_scatsys_translation_booster *qpms_scatsys_translation_booster_create(
+        const qpms_scatsys_ss *ss) {
+    const qpms_ss_pi_t np = ss->p_count;
+    TODO;
+}
+
diff --git a/qpms/scatsystem.c b/qpms/scatsystem.c
index c3bb86c..4a9a326 100644
--- a/qpms/scatsystem.c
+++ b/qpms/scatsystem.c
@@ -143,7 +143,6 @@ static void add_orbit_type(qpms_scatsys_t *ss, const qpms_ss_orbit_type_t *ot_cu
   ss->orbit_type_count++;
 }
 
-
 // Almost 200 lines. This whole thing deserves a rewrite!
 qpms_scatsys_at_omega_t *qpms_scatsys_apply_symmetry(const qpms_scatsys_t *orig,
     const qpms_finite_group_t *sym, complex double omega, 
diff --git a/qpms/scatsystem.h b/qpms/scatsystem.h
index 5c74c1f..5023fc2 100644
--- a/qpms/scatsystem.h
+++ b/qpms/scatsystem.h
@@ -133,7 +133,7 @@ typedef struct qpms_ss_derived_tmatrix_t {
 
 
 struct qpms_trans_calculator;
-struct qpms_epsmu_generator_t;
+struct qpms_scatsys_translation_booster;
 
 typedef struct qpms_scatsys_t {
 	struct qpms_epsmu_generator_t medium; ///< Optical properties of the background medium.
@@ -188,6 +188,9 @@ typedef struct qpms_scatsys_t {
 	char *otspace_end;
 	double lenscale; // radius of the array, used as a relative tolerance measure
 	struct qpms_trans_calculator *c;
+	// Internal metadata for faster translation matrix evaluation
+	struct qpms_scatsys_translation_booster *tbooster;
+
 } qpms_scatsys_t;
 
 /// Retrieve the bspec of \a tmi'th element of \a ss->tm.