Found multithreaded Cholesky almost 10 times faster than single-threaded

for n=2300, 16 threads

src/main/java/com/elphel/imagej/correction/Eyesis_Correction.java

@@ -96,6 +96,8 @@ import com.elphel.imagej.cameras.CLTParameters;
 import com.elphel.imagej.cameras.ColorProcParameters;
 import com.elphel.imagej.cameras.EyesisCorrectionParameters;
 import com.elphel.imagej.cameras.ThermalColor;
+import com.elphel.imagej.common.CholeskyLDLTMulti;
+import com.elphel.imagej.common.CholeskyLLTMulti;
 import com.elphel.imagej.common.DoubleFHT;
 import com.elphel.imagej.common.DoubleGaussianBlur;
 import com.elphel.imagej.common.GenericJTabbedDialog;
@@ -865,6 +867,8 @@ public class Eyesis_Correction implements PlugIn, ActionListener {
 			addButton("Vegetation LMA", panelOrange, color_process);
 			addButton("Combine LMA Segments", panelOrange, color_process);
 			addButton("Generate LWIR target", panelOrange, color_process);
+			addButton("Test LDLT Cholesky", panelOrange, color_process);
+			addButton("Test LLT Cholesky",  panelOrange, color_process);
 			plugInFrame.add(panelOrange);
 		}
 		plugInFrame.pack();
@@ -5807,8 +5811,20 @@ public class Eyesis_Correction implements PlugIn, ActionListener {
 					SYNC_COMMAND, // // SyncCommand  SYNC_COMMAND,
 					CLT_PARAMETERS, //CLTParameters    clt_parameters,
 					true); //boolean combine_segments);			
-		} else if (label.equals("Generate LWIR target")) {
-			VegetationSegment.generateSineTarget();	
+		} else if (label.equals("Test LDLT Cholesky")) {
+			ImagePlus imp_sel = WindowManager.getCurrentImage();
+			if (imp_sel == null) {
+				IJ.showMessage("Error", "No images selected");
+				return;
+			}
+			CholeskyLDLTMulti.testCholesky(imp_sel); // ImagePlus imp.);	 
+		} else if (label.equals("Test LLT Cholesky")) {
+			ImagePlus imp_sel = WindowManager.getCurrentImage();
+			if (imp_sel == null) {
+				IJ.showMessage("Error", "No images selected");
+				return;
+			}
+			CholeskyLLTMulti.testCholesky(imp_sel); // ImagePlus imp.);	 
 		}
 		//
 	}

src/main/java/com/elphel/imagej/vegetation/VegetationLMA.java

@@ -1907,9 +1907,32 @@ public class VegetationLMA {
 		Matrix mdelta_cholesky = choleskyDecomposition.solve(jty);
 		Matrix mdelta_cholesky_multi = choleskyLDLTMulti.solve(jty);
 		 */
-		CholeskyLDLTMulti.testCholesky(
-				wjtjlambda, // Matrix wjtjlambda,
-				jty);
+		boolean save_cholesky = true;
+		boolean debug_cholesky = true;
+		if (save_cholesky) {
+			int dbg_n = wjtjlambda.getRowDimension();
+			double [] dbg_a0 = wjtjlambda.getRowPackedCopy();
+			double [] dbg_a = new double[dbg_n*(dbg_n+1)];
+			for (int i = 0; i < dbg_n; i++) {
+				System.arraycopy(
+						dbg_a0,
+						i*dbg_n,
+						dbg_a,
+						i*(dbg_n+1),
+						dbg_n);
+				dbg_a[(i+1)*(dbg_n+1)-1] = jty.get(i,0);
+			}
+			ShowDoubleFloatArrays.showArrays(
+					dbg_a, // double[] pixels,
+					dbg_n+1, // int width,
+					dbg_n, // int height,
+					"spd_a_"+debug_iter); // String title)
+		}
+		if (debug_cholesky) {
+			CholeskyLDLTMulti.testCholesky(
+					wjtjlambda, // Matrix wjtjlambda,
+					jty);
+		}
 		if (debug_level>2) {
 			System.out.println("mdelta");
 			mdelta.print(18, 6);