title: Print a matrix stored as a SparseMatrixStructure
body: <p>I am working with Apple's Accelerate framework, using Sparse Matrix operations.</p>
  <p>I have created a sparse matrix thus:</p>
  <pre><code>    var  values: Array&lt;Double&gt; = [0.125, 0.08, -0.01, 0.405, -0.02, 0.005]
  
      var rowIndices: [Int32] = [0, 1, 2,     // Column 0
                                 3, 4,     // Column 1
                                 5 ]           // Column 3
       
      var columnStarts = [0, 3, 5, 6]
  
  let structure: SparseMatrixStructure = rowIndices.withUnsafeMutableBufferPointer { rowIndicesPtr in
          columnStarts.withUnsafeMutableBufferPointer { columnStartsPtr in
              var attributes = SparseAttributes_t()
              attributes.triangle = SparseLowerTriangle
              attributes.kind = SparseSymmetric
              
              return SparseMatrixStructure(
                  rowCount: 3,
                  columnCount: 3,
                  columnStarts: columnStartsPtr.baseAddress!,
                  rowIndices: rowIndicesPtr.baseAddress!,
                  attributes: attributes,
                  blockSize: 1
              )
          }
  </code></pre>
  <p>I am making a call to factorise the matrix:</p>
  <pre><code> let llt: SparseOpaqueFactorization_Double = values.withUnsafeMutableBufferPointer { valuesPtr in
          let a = SparseMatrix_Double(
              structure: structure,
              data: valuesPtr.baseAddress!
          )
          
          return SparseFactor(SparseFactorizationCholesky, a)
      }
  </code></pre>
  <p>I really need to check what the result is of the factorisation - i.e. print out the result. Can't see any way of even getting the result, let alone print it out.</p>
  <p>Can anyone help me understand how to retrieve the result and print it?</p>