diff --git a/src/ivoc/ocmatrix.cpp b/src/ivoc/ocmatrix.cpp
index dda8336e00..e0e6843814 100644
--- a/src/ivoc/ocmatrix.cpp
+++ b/src/ivoc/ocmatrix.cpp
@@ -232,7 +232,11 @@ double* OcSparseMatrix::mep(int i, int j) {
 }
 
 void OcSparseMatrix::zero() {
-    m_.setZero();
+    for (int k = 0; k < m_.outerSize(); ++k) {
+        for (decltype(m_)::InnerIterator it(m_, k); it; ++it) {
+            it.valueRef() = 0.;
+        }
+    }
 }
 
 double OcSparseMatrix::getval(int i, int j) {
@@ -288,7 +292,7 @@ void OcSparseMatrix::setdiag(int k, Vect* in) {
         }
     } else {
         for (int i = -k, j = 0; i < row && j < col; ++i, ++j) {
-            m_.coeffRef(i, j) = in->elem(i);
+            m_.coeffRef(i, j) = in->elem(j);
         }
     }
 }
@@ -313,8 +317,15 @@ void OcSparseMatrix::ident(void) {
 
 void OcSparseMatrix::setdiag(int k, double in) {
     int row = m_.rows();
-    for (int i = 0; i < row; ++i) {
-        m_.coeffRef(i, i) = in;
+    int col = m_.cols();
+    if (k >= 0) {
+        for (int i = 0, j = k; i < row && j < col; ++i, ++j) {
+            m_.coeffRef(i, j) = in;
+        }
+    } else {
+        for (int i = -k, j = 0; i < row && j < col; ++i, ++j) {
+            m_.coeffRef(i, j) = in;
+        }
     }
 }