diff --git a/src/maths/sparse/spAllocate.c b/src/maths/sparse/spAllocate.c
index bfad2a2fb..b8afd886f 100644
--- a/src/maths/sparse/spAllocate.c
+++ b/src/maths/sparse/spAllocate.c
@@ -202,7 +202,7 @@ int  AllocatedSize;
     Matrix->FillinsRemaining = 0;
 
     RecordAllocation( Matrix, (void *)Matrix );
-    if (Matrix->Error == spNO_MEMORY) goto MemoryError;
+    if (Matrix->Error == spNO_MEMORY) goto MemoryError; /* FIXME: Use of memory after free */
 
 /* Take out the trash. */
     Matrix->TrashCan.Real = 0.0;
diff --git a/src/maths/sparse/spBuild.c b/src/maths/sparse/spBuild.c
index 81b5885df..2ce9471be 100644
--- a/src/maths/sparse/spBuild.c
+++ b/src/maths/sparse/spBuild.c
@@ -185,7 +185,7 @@ spFindElement(
 )
 {
 register ElementPtr  pElement;
-int StartAt;
+int StartAt = 0;
 long int Min = LARGEST_LONG_INTEGER;
 #define BorderRight 0   /* Start at left border, move right. */
 #define BorderDown  1   /* Start at top border, move down. */
diff --git a/src/maths/sparse/spFactor.c b/src/maths/sparse/spFactor.c
index 22293dd52..6ed0add0f 100644
--- a/src/maths/sparse/spFactor.c
+++ b/src/maths/sparse/spFactor.c
@@ -377,7 +377,7 @@ RealNumber Mult;
 
 /* Update column. */
             pColumn = Matrix->FirstInCol[Step];
-            while (pColumn->Row < Step)
+            while (pColumn->Row < Step) /* FIXME: Access to Row results in dereference of NULL pointer */
             {   pElement = Matrix->Diag[pColumn->Row];
                 pColumn->Real = Dest[pColumn->Row] * pElement->Real;
                 while ((pElement = pElement->NextInCol) != NULL)
@@ -409,7 +409,7 @@ RealNumber Mult;
 
 /* Update column. */
             pColumn = Matrix->FirstInCol[Step];
-            while (pColumn->Row < Step)
+            while (pColumn->Row < Step) /* FIXME: Access to Row results in dereference of NULL pointer */
             {   pElement = Matrix->Diag[pColumn->Row];
                 Mult = (*pDest[pColumn->Row] *= pElement->Real);
                 while ((pElement = pElement->NextInCol) != NULL)
@@ -486,7 +486,7 @@ ComplexNumber Mult, Pivot;
 
 /* Update column. */
             pColumn = Matrix->FirstInCol[Step];
-            while (pColumn->Row < Step)
+            while (pColumn->Row < Step) /* FIXME: Access to Row results in dereference of NULL pointer */
             {   pElement = Matrix->Diag[pColumn->Row];
                 /* Cmplx expr: Mult = Dest[pColumn->Row] * (1.0 / *pPivot). */
                 CMPLX_MULT(Mult, Dest[pColumn->Row], *pElement);
@@ -524,7 +524,7 @@ ComplexNumber Mult, Pivot;
 
 /* Update column. */
             pColumn = Matrix->FirstInCol[Step];
-            while (pColumn->Row < Step)
+            while (pColumn->Row < Step) /* FIXME: Access to Row results in dereference of NULL pointer */
             {   pElement = Matrix->Diag[pColumn->Row];
                 /* Cmplx expr: Mult = *pDest[pColumn->Row] * (1.0 / *pPivot). */
                 CMPLX_MULT(Mult, *pDest[pColumn->Row], *pElement);
@@ -656,7 +656,7 @@ BOOLEAN *DoRealDirect;
         }
 
         pColumn = Matrix->FirstInCol[Step];
-        while (pColumn->Row < Step)
+        while (pColumn->Row < Step) /* FIXME: Access to Row results in dereference of NULL pointer */
         {   pElement = Matrix->Diag[pColumn->Row];
             Nm[Step]++;
             while ((pElement = pElement->NextInCol) != NULL)
@@ -2530,7 +2530,7 @@ register  ElementPtr  pElement;
                 pElement = *ElementAboveRow2;
             }   while (pElement->Row < Row2);
 
-        ElementBelowRow2 = Element2->NextInCol;
+            ElementBelowRow2 = Element2->NextInCol;/* FIXME: ElementBelowRow2 is never read */
 
 /* Move Element2 to Row1. */
             *ElementAboveRow2 = Element2->NextInCol;
@@ -2675,7 +2675,7 @@ register   ElementPtr  pElement;
                 pElement = *ElementLeftOfCol2;
             }   while (pElement->Col < Col2);
 
-            ElementRightOfCol2 = Element2->NextInRow;
+            ElementRightOfCol2 = Element2->NextInRow; /* FIXME: ElementRightOfCol2 is never read */
 
 /* Move Element2 to Col1. */
             *ElementLeftOfCol2 = Element2->NextInRow;
diff --git a/src/maths/sparse/spUtils.c b/src/maths/sparse/spUtils.c
index 1eb3ec5fc..a932e086f 100644
--- a/src/maths/sparse/spUtils.c
+++ b/src/maths/sparse/spUtils.c
@@ -240,7 +240,7 @@ BOOLEAN  Swapped, AnotherPassNeeded;
         if (AnotherPassNeeded)
         {   for (J = StartAt; NOT Swapped AND (J <= Size); J++)
             {   if (Matrix->Diag[J] == NULL)
-                {   Twins = CountTwins( Matrix, J, &pTwin1, &pTwin2 );
+                {   Twins = CountTwins( Matrix, J, &pTwin1, &pTwin2 ); /* FIXME: Twins is never used */
                     SwapCols( Matrix, pTwin1, pTwin2 );
                     Swapped = YES;
                 }