From 4f11a9f8530178cfb510f11c7bc4b1829bbd0be4 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Wed, 6 Mar 2019 11:40:37 +0100
Subject: Keep track of the "un-centering" matrix, as well as the "centering"

This makes it easy to reverse the transformation, if required, which it
is when comparing centered cells.
---
 tests/centering_check.c      |  9 +++++----
 tests/transformation_check.c | 35 ++++++++++++++++++++++++++++++-----
 2 files changed, 35 insertions(+), 9 deletions(-)

(limited to 'tests')

diff --git a/tests/centering_check.c b/tests/centering_check.c
index 774af66b..cc553dd0 100644
--- a/tests/centering_check.c
+++ b/tests/centering_check.c
@@ -61,7 +61,8 @@ static int check_centering(double a, double b, double c,
 {
 	UnitCell *cell, *cref;
 	UnitCell *n;
-	IntegerMatrix *t;
+	IntegerMatrix *C;
+	RationalMatrix *Ci;
 	int fail = 0;
 	int i;
 	double asx, asy, asz;
@@ -86,12 +87,12 @@ static int check_centering(double a, double b, double c,
 	cell_free(cref);
 
 	check_cell(cell, "Input");
-	n = uncenter_cell(cell, &t);
+	n = uncenter_cell(cell, &C, &Ci);
 	if ( n != NULL ) {
 		STATUS("The back transformation is:\n");
-		intmat_print(t);
+		intmat_print(C);
 		if ( check_cell(n, "Output") ) fail = 1;
-		if ( intmat_is_identity(t) && ((cen=='P') || (cen=='R')) ) {
+		if ( intmat_is_identity(C) && ((cen=='P') || (cen=='R')) ) {
 			STATUS("Identity, as expected.\n");
 		} else {
 			cell_print(n);
diff --git a/tests/transformation_check.c b/tests/transformation_check.c
index c5dad16c..06521061 100644
--- a/tests/transformation_check.c
+++ b/tests/transformation_check.c
@@ -224,25 +224,50 @@ static int check_transformation(UnitCell *cell, IntegerMatrix *tfn,
 static int check_uncentering(UnitCell *cell)
 {
 	UnitCell *ct;
-	IntegerMatrix *tr;
+	IntegerMatrix *C;
+	RationalMatrix *Ci;
+	UnitCell *cback;
+	double a[9], b[9];
+	int i;
 	int fail = 0;
 
 	STATUS("-----------------------\n");
 
 	STATUS("----> Before transformation:\n");
-	cell_print(cell);
+	cell_print_full(cell);
 
-	ct = uncenter_cell(cell, &tr);
+	ct = uncenter_cell(cell, &C, &Ci);
 	if ( ct == NULL ) return 1;
 
 	STATUS("----> The primitive unit cell:\n");
 	cell_print(ct);
 
 	STATUS("----> The matrix to put the centering back:\n");
-	intmat_print(tr);
+	intmat_print(C);
+
+	STATUS("----> The recovered centered cell:\n");
+	cback = cell_transform_intmat(ct, C);
+	cell_print(cback);
+
+	cell_get_cartesian(cell, &a[0], &a[1], &a[2],
+	                         &a[3], &a[4], &a[5],
+	                         &a[6], &a[7], &a[8]);
+	cell_get_cartesian(cback, &b[0], &b[1], &b[2],
+	                          &b[3], &b[4], &b[5],
+	                          &b[6], &b[7], &b[8]);
+	for ( i=0; i<9; i++ ) {
+		if ( fabs(a[i] - b[i]) > 1e-12 ) {
+			fail = 1;
+		}
+	}
+
+	if ( fail ) {
+		ERROR("Original cell not recovered after back transformation\n");
+	}
 
-	fail = check_same_reflections(cell, ct);
+	fail += check_same_reflections(cell, ct);
 	cell_free(ct);
+	cell_free(cback);
 
 	return fail;
 }
-- 
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