2 files changed, 28 insertions, 0 deletions
diff --git a/libcrystfel/src/cell.c b/libcrystfel/src/cell.c
index e7c9dace..11aa83fa 100644
--- a/libcrystfel/src/cell.c
+++ b/libcrystfel/src/cell.c
@@ -784,6 +784,32 @@ UnitCellTransformation *tfn_identity()
 }
 
 
+
+/**
+ * tfn_from_intmat:
+ * @m: An %IntegerMatrix
+ *
+ * Returns: A %UnitCellTransformation corresponding to @m.
+ *
+ */
+UnitCellTransformation *tfn_from_intmat(IntegerMatrix *m)
+{
+	UnitCellTransformation *tfn;
+	int i, j;
+
+	tfn = tfn_identity();
+	if ( tfn == NULL ) return NULL;
+
+	for ( i=0; i<3; i++ ) {
+	for ( j=0; j<3; j++ ) {
+		gsl_matrix_set(tfn->m, i, j, intmat_get(m, i, j));
+	}
+	}
+
+	return tfn;
+}
+
+
 /**
  * tfn_combine:
  * @t: A %UnitCellTransformation
diff --git a/libcrystfel/src/cell.h b/libcrystfel/src/cell.h
index c7b8f8d6..cde25b07 100644
--- a/libcrystfel/src/cell.h
+++ b/libcrystfel/src/cell.h
@@ -38,6 +38,7 @@
 #endif
 
 #include "utils.h"
+#include "integer_matrix.h"
 
 /* A 3D vector in reciprocal space.
  * Note: Heavily abused to serve as a real space vector as well */
@@ -141,6 +142,7 @@ extern UnitCell *cell_transform_inverse(UnitCell *cell,
                                         UnitCellTransformation *t);
 
 extern UnitCellTransformation *tfn_identity(void);
+extern UnitCellTransformation *tfn_from_intmat(IntegerMatrix *m);
 extern void tfn_combine(UnitCellTransformation *t,
                         double *na, double *nb, double *nc);
 extern void tfn_print(UnitCellTransformation *t);