Add warning about monoclinic I cells when using Mosflm

1 files changed, 9 insertions, 0 deletions

diff --git a/libcrystfel/src/mosflm.c b/libcrystfel/src/mosflm.c
index 658727b1..cc71dc65 100644
--- a/libcrystfel/src/mosflm.c
+++ b/libcrystfel/src/mosflm.c
@@ -846,6 +846,15 @@ void *mosflm_prepare(IndexingMethod *indm, UnitCell *cell)
 	*indm &= INDEXING_METHOD_MASK
 	       | INDEXING_USE_LATTICE_TYPE | INDEXING_USE_CELL_PARAMETERS;
 
+	if ( (cell_get_centering(cell) == 'I')
+	  && (cell_get_lattice_type(cell) == L_MONOCLINIC) )
+	{
+		ERROR("WARNING: Mosflm always gives the monoclinic C cell in "
+		      "preference to the monoclinic I cell choice.\n");
+		ERROR("To get a higher indexing rate, convert your cell to the "
+		      "monoclinic C cell choice.\n");
+	}
+
 	mp = malloc(sizeof(struct mosflm_private));
 	if ( mp == NULL ) return NULL;