--- a/scripts/control/util/zgscal.m
+++ b/scripts/control/util/zgscal.m
@@ -44,27 +44,27 @@
   nmp = n+m+p;
 
   ## x_0 = x_{-1} = 0, r_0 = z
-  x = zeros(nmp,1);
+  x = zeros (nmp, 1);
   xk1 = x;
   xk2 = x;
   rk1 = z;
   k = 0;
 
   ## construct balancing least squares problem
-  F = eye(nmp);
-  for kk=1:nmp
-    F(1:nmp,kk) = zgfmul(a,b,c,d,F(:,kk));
+  F = eye (nmp);
+  for kk = 1:nmp
+    F(1:nmp,kk) = zgfmul (a, b, c, d, F(:,kk));
   endfor
 
-  [U,H,k1] = krylov(F,z,nmp,1e-12,1);
-  if(!issquare(H))
-    if(columns(H) != k1)
-      error("zgscal(tzero): k1=%d, columns(H)=%d",k1,columns(H));
-    elseif(rows(H) != k1+1)
-      error("zgscal: k1=%d, rows(H) = %d",k1,rows(H));
-    elseif ( norm(H(k1+1,:)) > 1e-12*norm(H,"inf") )
+  [U, H, k1] = krylov (F, z, nmp, 1e-12, 1);
+  if (! issquare (H))
+    if (columns (H) != k1)
+      error ("zgscal(tzero): k1=%d, columns(H)=%d", k1, columns (H));
+    elseif (rows (H) != k1+1)
+      error ("zgscal: k1=%d, rows(H) = %d", k1, rows (H));
+    elseif (norm (H(k1+1,:)) > 1e-12*norm (H, "inf"))
       zgscal_last_row_of_H = H(k1+1,:)
-      error("zgscal: last row of H nonzero (norm(H)=%e)",norm(H,"inf"))
+      error ("zgscal: last row of H nonzero (norm(H)=%e)", norm (H, "inf"))
     endif
     H = H(1:k1,1:k1);
     U = U(:,1:k1);
@@ -72,8 +72,8 @@
 
   ## tridiagonal H can still be rank deficient, so do permuted qr
   ## factorization
-  [qq,rr,pp] = qr(H);   # H = qq*rr*pp'
-  nn = rank(rr);
+  [qq, rr, pp] = qr (H);   # H = qq*rr*pp'
+  nn = rank (rr);
   qq = qq(:,1:nn);
   rr = rr(1:nn,:);            # rr may not be square, but "\" does least
   xx = U*pp*(rr\qq'*(U'*z));  # squares solution, so this works
@@ -86,38 +86,41 @@
   ## so for now I'm solving it with the krylov routine.
 
   ## initialize residual error norm
-  rnorm = norm(rk1,1);
+  rnorm = norm (rk1, 1);
 
   xnorm = 0;
-  fnorm = 1e-12 * norm([a,b;c,d],1);
+  fnorm = 1e-12 * norm ([a, b; c, d], 1);
 
-  ## dummy defines for MATHTOOLS compiler
-  gamk2 = 0;      omega1 = 0;      ztmz2 = 0;
+  gamk2 = 0;
+  omega1 = 0;
+  ztmz2 = 0;
 
   ## do until small changes to x
   len_x = length(x);
-  while ((k < 2*len_x) & (xnorm> 0.5) & (rnorm>fnorm))|(k == 0)
-    k = k+1;
+  while ((k < 2*len_x && xnorm > 0.5 && rnorm > fnorm) || k == 0)
+    k++;
 
     ## solve F_d z_{k-1} = r_{k-1}
-    zk1= zgfslv(n,m,p,rk1);
+    zk1= zgfslv (n, m, p, rk1);
 
     ## Generalized CG iteration
     ## gamk1 = (zk1'*F_d*zk1)/(zk1'*F*zk1);
     ztMz1 = zk1'*rk1;
-    gamk1 = ztMz1/(zk1'*zgfmul(a,b,c,d,zk1));
+    gamk1 = ztMz1/(zk1'*zgfmul (a, b, c, d, zk1));
 
-    if(rem(k,len_x) == 1) omega = 1;
-    else                  omega = 1/(1-gamk1*ztMz1/(gamk2*omega1*ztmz2));
+    if (rem (k, len_x) == 1)
+      omega = 1;
+    else
+      omega = 1/(1-gamk1*ztMz1/(gamk2*omega1*ztmz2));
     endif
 
     ## store x in xk2 to save space
     xk2 = xk2 + omega*(gamk1*zk1 + xk1 - xk2);
 
     ## compute new residual error: rk = z - F xk, check end conditions
-    rk1 = z - zgfmul(a,b,c,d,xk2);
-    rnorm = norm(rk1);
-    xnorm = max(abs(xk1 - xk2));
+    rk1 = z - zgfmul (a, b, c, d, xk2);
+    rnorm = norm (rk1);
+    xnorm = max (abs (xk1 - xk2));
 
     ## printf("zgscal: k=%d, gamk1=%e, gamk2=%e, \nztMz1=%e ztmz2=%e\n", ...
     ##   k,gamk1, gamk2, ztMz1, ztmz2);
@@ -129,21 +132,22 @@
     gamk2 = gamk1;
     omega1 = omega;
     ztmz2 = ztMz1;
-    [xk1,xk2] = swap(xk1,xk2);
+    [xk1, xk2] = swap (xk1, xk2);
   endwhile
   x = xk2;
 
   ## check convergence
-  if (xnorm> 0.5 & rnorm>fnorm)
-    warning("zgscal(tzero): GCG iteration failed; solving with pinv");
+  if (xnorm> 0.5 && rnorm > fnorm)
+    warning ("zgscal(tzero): GCG iteration failed; solving with pinv");
 
     ## perform brute force least squares; construct F
-    Am = eye(nmp);
-    for ii=1:nmp
-      Am(:,ii) = zgfmul(a,b,c,d,Am(:,ii));
+    Am = eye (nmp);
+    for ii = 1:nmp
+      Am(:,ii) = zgfmul (a, b, c, d, Am(:,ii));
     endfor
 
     ## now solve with qr factorization
-    x = pinv(Am)*z;
+    x = pinv (Am) * z;
   endif
+
 endfunction