diff --git a/ChangeLog b/ChangeLog
index abcf288e6..0724f9ee4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2004-01-20  Paolo Nenzi <p.nenzi@ieee.org>
+
+	*   src/maths/ni/*: Cleaned up code removing unnecessary includes.
+
 2004-01-15  Paolo Nenzi <p.nenzi@ieee.org>
 
 	*   src/spicelib/devices/{cccs,ccvs,vccs,vcvs}/*: cleaned up the code.
diff --git a/src/maths/ni/niaciter.c b/src/maths/ni/niaciter.c
index 02c5eb8f5..1e075a355 100644
--- a/src/maths/ni/niaciter.c
+++ b/src/maths/ni/niaciter.c
@@ -15,7 +15,6 @@ Modified 1999 Emmanuel Rouat
      */
 
 #include "ngspice.h"
-#include <stdio.h>
 #include "trandefs.h"
 #include "cktdefs.h"
 #include "sperror.h"
@@ -23,7 +22,7 @@ Modified 1999 Emmanuel Rouat
 
 
 int
-NIacIter(register CKTcircuit *ckt)
+NIacIter(CKTcircuit *ckt)
 {
     int error;
     int ignore;
diff --git a/src/maths/ni/nicomcof.c b/src/maths/ni/nicomcof.c
index 59798dc2d..9b6c1e9c4 100644
--- a/src/maths/ni/nicomcof.c
+++ b/src/maths/ni/nicomcof.c
@@ -4,7 +4,6 @@ Author: 1985 Thomas L. Quarles
 **********/
 
 #include "ngspice.h"
-#include <stdio.h>
 #include "cktdefs.h"
 #include "sperror.h"
 #include "nicomcof.h"
diff --git a/src/maths/ni/niconv.c b/src/maths/ni/niconv.c
index ed293be81..6fac8b5b6 100644
--- a/src/maths/ni/niconv.c
+++ b/src/maths/ni/niconv.c
@@ -11,18 +11,17 @@ Author: 1985 Thomas L. Quarles
  */
 
 #include "ngspice.h"
-#include <stdio.h>
 #include "cktdefs.h"
 #include "smpdefs.h"
 #include "niconv.h"
 
 
 int
-NIconvTest(register CKTcircuit *ckt)
+NIconvTest(CKTcircuit *ckt)
 {
-    register int i; /* generic loop variable */
-    register int size;  /* size of the matrix */
-    register CKTnode *node; /* current matrix entry */
+    int i; /* generic loop variable */
+    int size;  /* size of the matrix */
+    CKTnode *node; /* current matrix entry */
     double old;
     double new;
     double tol;
diff --git a/src/maths/ni/nidest.c b/src/maths/ni/nidest.c
index 199ea24c4..0c56e44a2 100644
--- a/src/maths/ni/nidest.c
+++ b/src/maths/ni/nidest.c
@@ -15,7 +15,7 @@ Author: 1985 Thomas L. Quarles
 
 
 void
-NIdestroy(register CKTcircuit *ckt)
+NIdestroy(CKTcircuit *ckt)
 {
     if (ckt->CKTmatrix)
 	SMPdestroy(ckt->CKTmatrix);
diff --git a/src/maths/ni/niditer.c b/src/maths/ni/niditer.c
index 1fc447b35..715882c37 100644
--- a/src/maths/ni/niditer.c
+++ b/src/maths/ni/niditer.c
@@ -13,7 +13,6 @@ Author: 1988 Jaijeet S. Roychowdhury
      */
 
 #include "ngspice.h"
-#include <stdio.h>
 #include "trandefs.h"
 #include "cktdefs.h"
 #include "sperror.h"
@@ -21,7 +20,7 @@ Author: 1988 Jaijeet S. Roychowdhury
 
 
 int
-NIdIter(register CKTcircuit *ckt)
+NIdIter(CKTcircuit *ckt)
 {
     int error;
     int ignore;
diff --git a/src/maths/ni/niinit.c b/src/maths/ni/niinit.c
index e8a0ac4a3..952936317 100644
--- a/src/maths/ni/niinit.c
+++ b/src/maths/ni/niinit.c
@@ -13,7 +13,6 @@ Author: 1985 Thomas L. Quarles
 
 #include "ngspice.h"
 #include "cktdefs.h"
-#include <stdio.h>
 #include "sperror.h"
 #include "smpdefs.h"
 #include "niinit.h"
diff --git a/src/maths/ni/niinteg.c b/src/maths/ni/niinteg.c
index 6ccce77b3..d25e3b048 100644
--- a/src/maths/ni/niinteg.c
+++ b/src/maths/ni/niinteg.c
@@ -9,7 +9,6 @@ Author: 1985 Thomas L. Quarles
  */
 
 #include "ngspice.h"
-#include <stdio.h>
 #include "cktdefs.h"
 #include "sperror.h"
 #include "niinteg.h"
@@ -17,7 +16,7 @@ Author: 1985 Thomas L. Quarles
 #define ccap qcap+1
 
 int
-NIintegrate(register CKTcircuit *ckt, double *geq, double *ceq, double cap, int qcap)
+NIintegrate(CKTcircuit *ckt, double *geq, double *ceq, double cap, int qcap)
 {
     static char *ordmsg = "Illegal integration order";
     static char *methodmsg = "Unknown integration method";
diff --git a/src/maths/ni/niiter.c b/src/maths/ni/niiter.c
index 2f57fb5e9..61583eaee 100644
--- a/src/maths/ni/niiter.c
+++ b/src/maths/ni/niiter.c
@@ -14,7 +14,6 @@ Modified: 2001 AlansFixes
  */
 
 #include "ngspice.h"
-#include <stdio.h>
 #include "trandefs.h"
 #include "cktdefs.h"
 #include "smpdefs.h"
@@ -25,7 +24,7 @@ Modified: 2001 AlansFixes
 /* NIiter() - return value is non-zero for convergence failure */
 
 int
-NIiter(register CKTcircuit *ckt, int maxIter)
+NIiter(CKTcircuit *ckt, int maxIter)
 {
     int iterno;
     int ipass;
diff --git a/src/maths/ni/nipred.c b/src/maths/ni/nipred.c
index 574411ac0..d92b2f699 100644
--- a/src/maths/ni/nipred.c
+++ b/src/maths/ni/nipred.c
@@ -13,7 +13,6 @@ Author: 1985 Thomas L. Quarles
      */
 
 #include "ngspice.h"
-#include <stdio.h>
 #include "trandefs.h"
 #include "cktdefs.h"
 #include "sperror.h"
@@ -23,13 +22,13 @@ Author: 1985 Thomas L. Quarles
 
 #ifdef PREDICTOR
 int
-NIpred(register CKTcircuit * ckt)
+NIpred(CKTcircuit * ckt)
     
 {
     int i;
     double *temp;
     int size;
-    register CKTnode *node;
+    CKTnode *node;
 
     /* for our prediction, we have:
      *  ckt->CKTrhs[] is the current solution
diff --git a/src/maths/ni/nisenre.c b/src/maths/ni/nisenre.c
index fa271fe3d..f0b27044f 100644
--- a/src/maths/ni/nisenre.c
+++ b/src/maths/ni/nisenre.c
@@ -13,7 +13,6 @@ Author: 1985 Thomas L. Quarles
 
 #include "ngspice.h"
 #include "cktdefs.h"
-#include <stdio.h>
 #include "smpdefs.h"
 #include "sperror.h"
 #include "nisenre.h"
@@ -23,9 +22,9 @@ Author: 1985 Thomas L. Quarles
 (type *) MALLOC((size)*sizeof(type))) == NULL) return(E_NOMEM);
 
 int
-NIsenReinit(register CKTcircuit *ckt)
+NIsenReinit(CKTcircuit *ckt)
 {
-    register int size;
+    int size;
     int senparms;
     int i;