diff --git a/CMakeLists.txt b/CMakeLists.txt
index f94f617f23..58eabe7ed5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -83,6 +83,8 @@ check_symbol_exists ( fmax "math.h" NO_LIBM )
 # code coverage and build type
 #-------------------------------------------------------------------------------
 
+set (CMAKE_C_FLAGS_RELEASE "-O3 -g")    # FIXME
+
 # To compile with test coverage:
 #   cd build
 #   cmake -DCOVERAGE=1 ..
@@ -247,6 +249,11 @@ elseif ( "${CMAKE_C_COMPILER_ID}" STREQUAL "Intel" )
     #if ( CMAKE_C_COMPILER_VERSION VERSION_LESS 18.0 )
     #    message ( FATAL_ERROR "icc version must be at least 18.0" )
     #endif ( )
+elseif ( "${CMAKE_C_COMPILER_ID}" STREQUAL "AppleClang" )
+    # options for Apple Clang
+    # FIXME
+#    set ( CMAKE_C_FLAGS  "${CMAKE_C_FLAGS} -fsanitize=address" )
+#    set ( CMAKE_C_FLAGS  "${CMAKE_C_FLAGS} -fsanitize=thread" )
 elseif ( "${CMAKE_C_COMPILER_ID}" STREQUAL "Clang" AND NOT "${CMAKE_C_COMPILER_FRONTEND_VARIANT}" STREQUAL "MSVC" )
     # options for clang
     set ( CMAKE_C_FLAGS  "${CMAKE_C_FLAGS} -O3 " )
diff --git a/experimental/test/test_BF.c b/experimental/test/test_BF.c
index f4232dcb78..84ab741da6 100644
--- a/experimental/test/test_BF.c
+++ b/experimental/test/test_BF.c
@@ -151,15 +151,15 @@ void test_BF (void)
         OK (GrB_Matrix_new (&AT, GrB_FP64, ncols, nrows)) ;
         OK (GrB_transpose (AT, NULL, NULL, A, NULL)) ;
         double transpose_time = LAGraph_WallClockTime ( ) - tt ;
-        fprintf (stderr, "transpose     time: %g\n", transpose_time) ;
+//      fprintf (stderr, "transpose     time: %g\n", transpose_time) ;
 
         //----------------------------------------------------------------------
         // get the source node
         //----------------------------------------------------------------------
 
         GrB_Index s = 0 ;
-        fprintf (stderr, "\n==========input graph: nodes: %g edges: %g "
-            "source node: %g\n", (double) n, (double) nvals, (double) s) ;
+//      fprintf (stderr, "\n==========input graph: nodes: %g edges: %g "
+//          "source node: %g\n", (double) n, (double) nvals, (double) s) ;
 
         //----------------------------------------------------------------------
         // run 1 or 2 trials (2 negative weight cycles)
@@ -192,8 +192,8 @@ void test_BF (void)
             // stop the timer
             t5 = LAGraph_WallClockTime ( ) - t5 ;
             t5 = t5 / ntrials;
-            fprintf (stderr, "BF_full1      time: %12.6e (sec), rate:"
-                " %g (1e6 edges/sec)\n", t5, 1e-6*((double) nvals) / t5) ;
+//          fprintf (stderr, "BF_full1      time: %12.6e (sec), rate:"
+//              " %g (1e6 edges/sec)\n", t5, 1e-6*((double) nvals) / t5) ;
 
             //------------------------------------------------------------------
             // run LAGraph_BF_full1a before setting the diagonal to 0
@@ -214,8 +214,8 @@ void test_BF (void)
             // stop the timer
             t5a = LAGraph_WallClockTime ( ) - t5a ;
             t5a = t5a / ntrials;
-            fprintf (stderr, "BF_full1a     time: %12.6e (sec), rate:"
-                " %g (1e6 edges/sec)\n", t5a, 1e-6*((double) nvals) / t5a) ;
+//          fprintf (stderr, "BF_full1a     time: %12.6e (sec), rate:"
+//              " %g (1e6 edges/sec)\n", t5a, 1e-6*((double) nvals) / t5a) ;
 
             //------------------------------------------------------------------
             // run LAGraph_BF_full2 before setting the diagonal to 0
@@ -236,8 +236,8 @@ void test_BF (void)
             // stop the timer
             t6 = LAGraph_WallClockTime ( ) - t6 ;
             t6 = t6 / ntrials;
-            fprintf (stderr, "BF_full2      time: %12.6e (sec), rate:"
-                " %g (1e6 edges/sec)\n", t6, 1e-6*((double) nvals) / t6) ;
+//          fprintf (stderr, "BF_full2      time: %12.6e (sec), rate:"
+//              " %g (1e6 edges/sec)\n", t6, 1e-6*((double) nvals) / t6) ;
 
             //------------------------------------------------------------------
             // run the LAGraph_BF_full on node s
@@ -259,9 +259,9 @@ void test_BF (void)
             // stop the timer
             t1 = LAGraph_WallClockTime ( ) - t1 ;
             t1 = t1 / ntrials;
-            fprintf (stderr, "BF_full       time: %12.6e (sec), rate:"
-                " %g (1e6 edges/sec)\n", t1, 1e-6*((double) nvals) / t1) ;
-            fprintf (stderr, "t(BF_full1) / t(BF_full):      %g\n", t5/t1) ;
+//          fprintf (stderr, "BF_full       time: %12.6e (sec), rate:"
+//              " %g (1e6 edges/sec)\n", t1, 1e-6*((double) nvals) / t1) ;
+//          fprintf (stderr, "t(BF_full1) / t(BF_full):      %g\n", t5/t1) ;
 
             //------------------------------------------------------------------
             // run the BF on node s with LAGraph_BF_basic
@@ -280,9 +280,9 @@ void test_BF (void)
             // stop the timer
             t2 = LAGraph_WallClockTime ( ) - t2 ;
             t2 = t2 / ntrials;
-            fprintf (stderr, "BF_basic      time: %12.6e (sec), rate:"
-                " %g (1e6 edges/sec)\n", t2, 1e-6*((double) nvals) / t2) ;
-            fprintf (stderr, "speedup of BF_basic:       %g\n", t1/t2) ;
+//          fprintf (stderr, "BF_basic      time: %12.6e (sec), rate:"
+//              " %g (1e6 edges/sec)\n", t2, 1e-6*((double) nvals) / t2) ;
+//          fprintf (stderr, "speedup of BF_basic:       %g\n", t1/t2) ;
 
             //------------------------------------------------------------------
             // run the BF on node s with LAGraph_pure_c
@@ -303,9 +303,9 @@ void test_BF (void)
             // stop the timer
             t3 = LAGraph_WallClockTime ( ) - t3 ;
             t3 = t3 / ntrials;
-            fprintf (stderr, "BF_pure_c_double  : %12.6e (sec), rate:"
-                " %g (1e6 edges/sec)\n", t3, 1e-6*((double) nvals) / t3) ;
-            fprintf (stderr, "speedup of BF_pure_c:      %g\n", t1/t3) ;
+//          fprintf (stderr, "BF_pure_c_double  : %12.6e (sec), rate:"
+//              " %g (1e6 edges/sec)\n", t3, 1e-6*((double) nvals) / t3) ;
+//          fprintf (stderr, "speedup of BF_pure_c:      %g\n", t1/t3) ;
 
             if (has_integer_weights)
             {
@@ -337,9 +337,9 @@ void test_BF (void)
             // stop the timer
             t4 = LAGraph_WallClockTime ( ) - t4 ;
             t4 = t4 / ntrials;
-            fprintf (stderr, "BF_full_mxv   time: %12.6e (sec), rate:"
-                " %g (1e6 edges/sec)\n", t4, 1e-6*((double) nvals) / t4) ;
-            fprintf (stderr, "speedup of BF_full_mxv:    %g\n", t1/t4) ;
+//          fprintf (stderr, "BF_full_mxv   time: %12.6e (sec), rate:"
+//              " %g (1e6 edges/sec)\n", t4, 1e-6*((double) nvals) / t4) ;
+//          fprintf (stderr, "speedup of BF_full_mxv:    %g\n", t1/t4) ;
 
             //------------------------------------------------------------------
             // run the BF on node s with LAGraph_BF_basic_mxv
@@ -358,9 +358,9 @@ void test_BF (void)
             // stop the timer
             t7 = LAGraph_WallClockTime ( ) - t7 ;
             t7 = t7 / ntrials;
-            fprintf (stderr, "BF_basic_mxv  time: %12.6e (sec), rate:"
-                " %g (1e6 edges/sec)\n", t7, 1e-6*((double) nvals) / t7) ;
-            fprintf (stderr, "speedup of BF_basic_mxv:   %g\n", t1/t7) ;
+//          fprintf (stderr, "BF_basic_mxv  time: %12.6e (sec), rate:"
+//              " %g (1e6 edges/sec)\n", t7, 1e-6*((double) nvals) / t7) ;
+//          fprintf (stderr, "speedup of BF_basic_mxv:   %g\n", t1/t7) ;
 
             //------------------------------------------------------------------
             // run the BF on node s with LAGraph_BF_basic_pushpull
diff --git a/experimental/test/test_SquareClustering.c b/experimental/test/test_SquareClustering.c
index b4e976aa6c..3e1a340bf4 100644
--- a/experimental/test/test_SquareClustering.c
+++ b/experimental/test/test_SquareClustering.c
@@ -57,6 +57,8 @@ bool is_close (double a, double b)
 void test_SquareClustering (void)
 {
     LAGraph_Init (msg) ;
+    GrB_set (GrB_GLOBAL, true, GxB_BURBLE) ;
+
 
     GrB_Matrix A = NULL ;
     LAGraph_Graph G = NULL ;
diff --git a/experimental/test/test_cdlp.c b/experimental/test/test_cdlp.c
index b30dadab45..d75e338736 100644
--- a/experimental/test/test_cdlp.c
+++ b/experimental/test/test_cdlp.c
@@ -80,11 +80,13 @@ void test_cdlp (void)
 
         // compute the communities with LAGraph_cdlp
         OK (LAGraph_cdlp (&c, G, 100, msg)) ;
-
         GrB_Index n ;
         OK (GrB_Vector_size (&n, c)) ;
         LAGraph_PrintLevel pr = (n <= 100) ? LAGraph_COMPLETE : LAGraph_SHORT ;
+        printf ("\ncdlp (computed result):\n") ;
+        OK (LAGraph_Vector_Print (c, pr, stdout, msg)) ;
 
+        // compute with another method
         GrB_Vector cgood = NULL ;
         OK (LAGraph_cdlp_withsort(&cgood, G, 100, msg)) ;
         OK (GrB_wait (cgood, GrB_MATERIALIZE)) ;