diff --git a/src/bivariate/quad_over_lin.c b/src/bivariate/quad_over_lin.c
index 35639ff..d3d5920 100644
--- a/src/bivariate/quad_over_lin.c
+++ b/src/bivariate/quad_over_lin.c
@@ -3,7 +3,9 @@
 #include "utils/CSC_Matrix.h"
 #include <assert.h>
 #include <math.h>
+#include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 // ------------------------------------------------------------------------------
 // Implementation of quad-over-lin. The second argument will always be a variable
@@ -231,7 +233,9 @@ static void wsum_hess_init(expr *node)
     else
     {
         /* TODO: implement */
-        assert(false && "not implemented");
+        fprintf(stderr, "Error in quad_over_lin wsum_hess_init: non-variable child "
+                        "not implemented\n");
+        exit(1);
     }
 }
 
@@ -288,7 +292,9 @@ static void eval_wsum_hess(expr *node, const double *w)
     else
     {
         /* TODO: implement */
-        assert(false && "not implemented");
+        fprintf(stderr, "Error in quad_over_lin eval_wsum_hess: non-variable child "
+                        "not implemented\n");
+        exit(1);
     }
 }
 
diff --git a/src/other/prod.c b/src/other/prod.c
index 2d62672..0dfbfbd 100644
--- a/src/other/prod.c
+++ b/src/other/prod.c
@@ -1,6 +1,7 @@
 #include "other.h"
 #include <assert.h>
 #include <math.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -62,7 +63,9 @@ static void jacobian_init(expr *node)
     }
     else
     {
-        assert(false && "not implemented");
+        fprintf(stderr,
+                "Error in prod jacobian_init: non-variable child not implemented\n");
+        exit(1);
     }
 }
 
@@ -94,7 +97,9 @@ static void eval_jacobian(expr *node)
     }
     else
     {
-        assert(false && "not implemented");
+        fprintf(stderr,
+                "Error in prod eval_jacobian: non-variable child not implemented\n");
+        exit(1);
     }
 }
 
@@ -133,7 +138,10 @@ static void wsum_hess_init(expr *node)
     }
     else
     {
-        assert(false && "not implemented");
+        fprintf(
+            stderr,
+            "Error in prod wsum_hess_init: non-variable child not implemented\n");
+        exit(1);
     }
 }
 
@@ -164,7 +172,10 @@ static void eval_wsum_hess(expr *node, const double *w)
     }
     else
     {
-        assert(false && "not implemented");
+        fprintf(
+            stderr,
+            "Error in prod eval_wsum_hess: non-variable child not implemented\n");
+        exit(1);
     }
 }
 
diff --git a/src/other/prod_axis_one.c b/src/other/prod_axis_one.c
index 600a20a..cd43229 100644
--- a/src/other/prod_axis_one.c
+++ b/src/other/prod_axis_one.c
@@ -84,7 +84,9 @@ static void jacobian_init(expr *node)
     }
     else
     {
-        assert(false && "child must be a variable");
+        fprintf(stderr,
+                "Error in prod_axis_one jacobian_init: child must be a variable\n");
+        exit(1);
     }
 }
 
@@ -125,7 +127,9 @@ static void eval_jacobian(expr *node)
     }
     else
     {
-        assert(false && "child must be a variable");
+        fprintf(stderr,
+                "Error in prod_axis_one eval_jacobian: child must be a variable\n");
+        exit(1);
     }
 }
 
@@ -173,7 +177,9 @@ static void wsum_hess_init(expr *node)
     }
     else
     {
-        assert(false && "child must be a variable");
+        fprintf(stderr,
+                "Error in prod_axis_one wsum_hess_init: child must be a variable\n");
+        exit(1);
     }
 }
 
@@ -350,7 +356,9 @@ static void eval_wsum_hess(expr *node, const double *w)
     }
     else
     {
-        assert(false && "child must be a variable");
+        fprintf(stderr,
+                "Error in prod_axis_one eval_wsum_hess: child must be a variable\n");
+        exit(1);
     }
 }
 
diff --git a/src/other/prod_axis_zero.c b/src/other/prod_axis_zero.c
index 191f6ff..ad85b6e 100644
--- a/src/other/prod_axis_zero.c
+++ b/src/other/prod_axis_zero.c
@@ -1,6 +1,7 @@
 #include "other.h"
 #include <assert.h>
 #include <math.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -78,7 +79,9 @@ static void jacobian_init(expr *node)
     }
     else
     {
-        assert(false && "child must be a variable");
+        fprintf(stderr,
+                "Error in prod_axis_zero jacobian_init: child must be a variable\n");
+        exit(1);
     }
 }
 
@@ -118,7 +121,9 @@ static void eval_jacobian(expr *node)
     }
     else
     {
-        assert(false && "child must be a variable");
+        fprintf(stderr,
+                "Error in prod_axis_zero eval_jacobian: child must be a variable\n");
+        exit(1);
     }
 }
 
@@ -164,7 +169,10 @@ static void wsum_hess_init(expr *node)
     }
     else
     {
-        assert(false && "child must be a variable");
+        fprintf(
+            stderr,
+            "Error in prod_axis_zero wsum_hess_init: child must be a variable\n");
+        exit(1);
     }
 }
 
@@ -306,7 +314,10 @@ static void eval_wsum_hess(expr *node, const double *w)
     }
     else
     {
-        assert(false && "child must be a variable");
+        fprintf(
+            stderr,
+            "Error in prod_axis_zero eval_wsum_hess: child must be a variable\n");
+        exit(1);
     }
 }