add comment about scaling in Euler Maruyama

mrirecon · Jul 19, 2024 · 76f1371 · 76f1371
1 parent 77f5718
commit 76f1371
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/src/iter/italgos.c b/src/iter/italgos.c
@@ -29,7 +29,6 @@
  *
  * Chambolle A, Pock, T. A First-Order Primal-Dual Algorithm for Convex Problems
  * with Applications to Imaging. J. Math. Imaging Vis. 2011; 40, 120-145.
- *
  */
 
 #include <math.h>
@@ -368,6 +367,10 @@ void eulermaruyama(int maxiter, float alpha,
 
 		iter_monitor(monitor, vops, x);
 
+		// the gradients are scaled so that with unitary operators the
+		// data is assumed to have complex Gaussian noise with s = 1
+		// (which cancels the 1/2 in the algorithm)
+
 		iter_op_call(op, r, x);		// r = A x
 		vops->xpay(N, -1., r, b);	// r = b - r = b - A x