diff --git a/src/TNL/Containers/Segments.h b/src/TNL/Containers/Segments.h
new file mode 100644
index 0000000000000000000000000000000000000000..99ea2235722cc0d3f7b594c95e42ab781800903b
--- /dev/null
+++ b/src/TNL/Containers/Segments.h
@@ -0,0 +1,29 @@
+/***************************************************************************
+ Segments.h - description
+ -------------------
+ begin : Nov 29, 2019
+ copyright : (C) 2019 by Tomas Oberhuber
+ email : tomas.oberhuber@fjfi.cvut.cz
+ ***************************************************************************/
+
+/* See Copyright Notice in tnl/Copyright */
+
+#pragma once
+
+namespace TNL {
+namespace Containers {
+
+template< typename Value,
+ typename Organization >
+class Segments
+{
+ public:
+
+ using ValueType = Value;
+ using OrganizationType = Organization;
+ using IndexType = typename Organization::IndexType;
+
+};
+
+} // namespace Conatiners
+} // namespace TNL
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diff --git a/src/TNL/Containers/Segments/CSR.h b/src/TNL/Containers/Segments/CSR.h
new file mode 100644
index 0000000000000000000000000000000000000000..3aa53e76cbda272ca828126e418fdc3fe43d069a
--- /dev/null
+++ b/src/TNL/Containers/Segments/CSR.h
@@ -0,0 +1,83 @@
+/***************************************************************************
+ CSR.h - description
+ -------------------
+ begin : Nov 29, 2019
+ copyright : (C) 2019 by Tomas Oberhuber
+ email : tomas.oberhuber@fjfi.cvut.cz
+ ***************************************************************************/
+
+/* See Copyright Notice in tnl/Copyright */
+
+#pragma once
+
+#include <TNL/Containers/Vector.h>
+
+namespace TNL {
+ namespace Containers {
+ namespace Segments {
+
+
+template< typename Device,
+ typename Index >
+class Segments
+{
+ public:
+
+ using DeviceType = Device;
+ using IndexType = Index;
+ using OffsetsHolder = Containers::Vector< IndexType, DeviceType, IndexType >;
+
+ CSR();
+
+ CSR( const SizesHolder& sizes );
+
+ CSR( const CSR& csr );
+
+ CSR( const CSR&& csr );
+
+ /**
+ * \brief Set number of segments
+ */
+ //void setSegmentsCount();
+
+ /**
+ * \brief Set sizes of particular segmenets.
+ */
+ template< typename SizesHolder = OffsetsHolder >
+ void setSizes( const SizesHolder& sizes )
+
+ /**
+ * \brief Number segments.
+ */
+ Index getSize() const;
+
+ Index getStorageSize() const;
+
+ IndexType getGlobalIndex( const Index segmentIdx, const Index localIdx ) const;
+
+ void getSegmentAndLocalIndex( const Index globalIdx, Index& segmentIdx, Index& localIdx ) const;
+
+ /***
+ * \brief Go over all segments and for each segment element call
+ * function 'f' with arguments 'args'
+ */
+ template< typename Function, typename... Args >
+ void forAll( Function& f, Args args ) const;
+
+ /***
+ * \brief Go over all segments and perform a reduction in each of them.
+ */
+ template< typename Fetch, typename Reduction, typename ResultKeeper, typename... Args >
+ void segmentsReduction( Fetch& fetch, Reduction& reduction, ResultKeeper& keeper, Args args );
+
+ protected:
+
+ OffsetsHolder offsets;
+
+};
+
+ } // namespace Segements
+ } // namespace Conatiners
+} // namespace TNL
+
+#include <TNL/Containers/Segments/CSR.h>
\ No newline at end of file
diff --git a/src/TNL/Containers/Segments/CSR.hpp b/src/TNL/Containers/Segments/CSR.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..ea45b40ba9d67b16203e0e7665859f5390653b9f
--- /dev/null
+++ b/src/TNL/Containers/Segments/CSR.hpp
@@ -0,0 +1,110 @@
+/***************************************************************************
+ CSR.hpp - description
+ -------------------
+ begin : Nov 29, 2019
+ copyright : (C) 2019 by Tomas Oberhuber
+ email : tomas.oberhuber@fjfi.cvut.cz
+ ***************************************************************************/
+
+/* See Copyright Notice in tnl/Copyright */
+
+#pragma once
+
+#include <TNL/Containers/Vector.h>
+#include <TNL/Algorithms/ParalleFor.h>
+#include <TNL/Containers/Segments/CSR.h>
+
+namespace TNL {
+ namespace Containers {
+ namespace Segments {
+
+
+template< typename Device,
+ typename Index >
+CSR< Device, Index >::
+CSR()
+{
+}
+
+template< typename Device,
+ typename Index >
+CSR< Device, Index >::
+CSR( const CSR& csr ) : offsets( csr.offsets )
+{
+}
+
+template< typename Device,
+ typename Index >
+CSR< Device, Index >::
+CSR( const CSR&& csr ) : offsets( std::move( csr.offsets ) )
+{
+
+}
+
+template< typename Device,
+ typename Index >
+CSR< Device, Index >::
+void setSegmentsCount( const IndexType& size )
+{
+ this->offsets.setSize( size + 1 );
+}
+
+template< typename Device,
+ typename Index >
+ template< typename SizesHolder = OffsetsHolder >
+CSR< Device, Index >::
+void setSizes( const SizesHolder& sizes )
+{
+ this->offsets.setSize( sizes.getSize() + 1 );
+ auto view = this->offsets.getView( 0, sizes.getSize() );
+ view = sizes;
+ this->offsets.setElement( sizes.getSize>(), 0 );
+ this->offsets.scan< Algorithms::ScanType::Exclusive >();
+}
+
+template< typename Device,
+ typename Index >
+CSR< Device, Index >::
+Index getSize() const
+{
+ return this->offsets.getSize() - 1;
+}
+
+template< typename Device,
+ typename Index >
+ template< typename Function, typename... Args >
+CSR< Device, Index >::
+void forAll( Function& f, Args args ) const
+{
+ const auto offsetsView = this->offsets.getView();
+ auto f = [=] __cuda_callable__ ( const IndexType i, f, args ) {
+ const IndexType begin = offsetsView[ i ];
+ const IndexType end = offsetsView[ i + 1 ];
+ for( IndexType j = begin; j < end; j++ )
+ f( i, j, args );
+ };
+ Algorithms::ParallelFor< Device >::exec( 0, this->getSize(), f );
+}
+
+template< typename Device,
+ typename Index >
+ template< typename Fetch, typename Reduction, typename ResultKeeper, typename Real, typename... Args >
+CSR< Device, Index >::
+void segmentsReduction( Fetch& fetch, Reduction& reduction, ResultKeeper& keeper, Real zero, Args args )
+{
+ const auto offsetsView = this->offsets.getView();
+ auto f = [=] __cuda_callable__ ( const IndexType i, f, args ) {
+ const IndexType begin = offsetsView[ i ];
+ const IndexType end = offsetsView[ i + 1 ];
+ Real aux( zero );
+ for( IndexType j = begin; j < end; j++ )
+ reduction( aux, fetch( i, j, args ) );
+ keeper( i, aux );
+ };
+ Algorithms::ParallelFor< Device >::exec( 0, this->getSize(), f );
+}
+
+
+ } // namespace Segements
+ } // namespace Conatiners
+} // namespace TNL
\ No newline at end of file