Set niter = -1 in snorm if no convergence (like in lsedc); simplify. …

…Improve lsedc doc.

core/snorm.m

@@ -17,7 +17,7 @@
 %    (default: NITER_MAX = 32).
 %
 %    [S,NITER] = SNORM(N,MV,MVA,...) also returns the number NITER of iterations
-%    performed.
+%    required for convergence. If NITER = -1, then convergence was not detected.
 %
 %    References:
 %
@@ -44,11 +44,9 @@
   x = rand(n,1);
   xnorm = norm(x);
   s = xnorm;
-  niter = 0;
 
   % main loop
-  while niter < niter_max
-    niter = niter + 1;
+  for niter = 1:niter_max
     x = x/xnorm;
     s_ = s;
 
@@ -68,6 +66,7 @@
     if abs(s - s_) <= s_*tol, return; end  % within tolerance
   end
 
-  % loop didn't return; maximum number of iterations reached
+  % loop didn't return; no convergence
+  niter = -1;
   warning('FLAM:snorm:maxIterCount','Maximum number of iterations reached.')
 end

misc/lsedc.m

@@ -15,15 +15,15 @@
 %    [X,CRES] = LSEDC(LSFUN,A,B,C,D,TAU) also returns the constraint residual
 %    matrix CRES upon termination.
 %
-%    [X,CRES,NITER] = LSEDC(LSFUN,A,B,C,D,TAU) further returns the number NITER
-%    of deferred correction iterations required for convergence. If NITER = -1,
-%    then convergence was not detected.
-%
-%    [X,CRES,NITER] = LSEDC(LSFUN,A,B,C,D,TAU,TOL) iterates until the constraint
+%    [X,CRES] = LSEDC(LSFUN,A,B,C,D,TAU,TOL) iterates until the constraint
 %    residual matrix has norm less than or equal to TOL (default: TOL = 1E-12).
 %
-%    [X,CRES,NITER] = LSEDC(LSFUN,A,B,C,D,TAU,TOL,NITER_MAX) uses at most
-%    NITER_MAX iterations (default: NITER_MAX = 8).
+%    [X,CRES] = LSEDC(LSFUN,A,B,C,D,TAU,TOL,NITER_MAX) uses at most NITER_MAX
+%    iterations (default: NITER_MAX = 8).
+%
+%    [X,CRES,NITER] = LSEDC(LSFUN,A,B,C,D,TAU,...) further returns the number
+%    NITER of iterations required for convergence. If NITER = -1, then
+%    convergence was not detected.
 %
 %    References:
 %