Restore the descriptors in CUSPARSE (#2746)

Author: amontoison

lib/cusparse/helpers.jl

@@ -36,6 +36,14 @@ end
 mutable struct CuDenseVectorDescriptor
     handle::cusparseDnVecDescr_t
 
+    function CuDenseVectorDescriptor(T::DataType, n::Integer)
+        desc_ref = Ref{cusparseDnVecDescr_t}()
+        cusparseCreateDnVec(desc_ref, n, CU_NULL, T)
+        obj = new(desc_ref[])
+        finalizer(cusparseDestroyDnVec, obj)
+        return obj
+    end
+
     function CuDenseVectorDescriptor(x::DenseCuVector)
         desc_ref = Ref{cusparseDnVecDescr_t}()
         cusparseCreateDnVec(desc_ref, length(x), x, eltype(x))
@@ -71,6 +79,18 @@ Base.unsafe_convert(::Type{cusparseSpVecDescr_t}, desc::CuSparseVectorDescriptor
 mutable struct CuDenseMatrixDescriptor
     handle::cusparseDnMatDescr_t
 
+    function CuDenseMatrixDescriptor(T::DataType, m::Integer, n::Integer; transposed::Bool=false)
+        desc_ref = Ref{cusparseDnMatDescr_t}()
+        if transposed
+            cusparseCreateDnMat(desc_ref, n, m, m, CU_NULL, T, 'R')
+        else
+            cusparseCreateDnMat(desc_ref, m, n, m, CU_NULL, T, 'C')
+        end
+        obj = new(desc_ref[])
+        finalizer(cusparseDestroyDnMat, obj)
+        return obj
+    end
+
     function CuDenseMatrixDescriptor(A::DenseCuMatrix; transposed::Bool=false)
         desc_ref = Ref{cusparseDnMatDescr_t}()
         if transposed