some optional debug prints

src/main/java/com/elphel/imagej/cuas/CuasMotion.java

@@ -1379,7 +1379,7 @@ public class CuasMotion {
 		final boolean [][] filter_target = new boolean [num_seq][num_tiles];
 		final double maxxy =   GPUTileProcessor.DTT_SIZE - 1 -lma_minxy; // lma_minxy=1 - prevent bottom row/righth column
 		final double minxy =  -GPUTileProcessor.DTT_SIZE     +lma_minxy; // lma_minxy=1 - prevent top row/left column 
-		
+		final int dbg_tile = -(33 + 34*80);
 		final Thread[] threads = ImageDtt.newThreadArray();
 		final AtomicInteger ai = new AtomicInteger(0);
 		for (int ithread = 0; ithread < threads.length; ithread++) {
@@ -1390,6 +1390,10 @@ public class CuasMotion {
 						for (int tileY = 0; tileY < tilesY; tileY++) {
 							for (int tileX = 0; tileX < tilesX; tileX++) {
 								int ntile = tileX + tilesX * tileY;
+							    if (ntile == dbg_tile) {
+							        System.out.println("filterTargetsLMA(): ntile = "+ntile);
+							    }
+
 								double [] lma_rslts = target_coords[nSeq][ntile];
 								if (lma_rslts != null) {
 									if (lma_rslts[CuasMotionLMA.RSLT_ITERS] < 0) { // fitting has not failed