[CUSOLVER] Fix Xgesvdr! (#2556)

Author: amontoison

lib/cusolver/dense_generic.jl

@@ -327,21 +327,22 @@ function Xgesvdr!(jobu::Char, jobv::Char, A::StridedCuMatrix{T}, k::Integer;
                   niters::Integer=2, p::Integer=2*k) where {T <: BlasFloat}
     m, n = size(A)
     ℓ = min(m,n)
+    p = min(p, ℓ-k)  # Ensure that p + k ≤ ℓ
     (1 ≤ k ≤ ℓ) || throw(ArgumentError("illegal choice of parameter k = $k, which must be between 1 and min(m,n) = $ℓ"))
     (k+p ≤ ℓ) || throw(ArgumentError("illegal choice of parameters k = $k and p = $p, which must satisfy k+p ≤ min(m,n) = $ℓ"))
     R = real(T)
     U = if jobu == 'S'
-        CuMatrix{T}(undef, m, k)
+        CuMatrix{T}(undef, m, m)
     elseif jobu == 'N'
-        CU_NULL
+        CuMatrix{T}(undef, m, ℓ)
     else
         throw(ArgumentError("jobu is incorrect. The values accepted are 'S' and 'N'."))
     end
     Σ = CuVector{R}(undef, ℓ)
     V = if jobv == 'S'
-        CuMatrix{T}(undef, n, k)
+        CuMatrix{T}(undef, n, n)
     elseif jobv == 'N'
-        CU_NULL
+        CuMatrix{T}(undef, n, ℓ)
     else
         throw(ArgumentError("jobv is incorrect. The values accepted are 'S' and 'N'."))
     end

test/libraries/cusolver/dense_generic.jl

@@ -171,22 +171,28 @@ p = 5
         @test A ≈ collect(U) * Diagonal(collect(Σ)) * collect(V)'
     end
 
-    # @testset "gesvdr!" begin
-    #     R = real(elty)
-    #     B = rand(elty,m,m)
-    #     FB = qr(B)
-    #     C = rand(elty,n,n)
-    #     FC = qr(C)
-    #     Σ = zeros(elty,m,n)
-    #     for i = 1:n
-    #         Σ[i,i] = i*one(R)
-    #     end
-    #     k = 3
-    #     A = FB.Q * Σ * FC.Q
-    #     d_A = CuMatrix(A)
-    #     U, Σ, V = CUSOLVER.Xgesvdr!('N', 'N', d_A, k)
-    #     @test A ≈ collect(U[:,1:n] * Diagonal(Σ) * V')
-    # end
+    @testset "gesvdr!" begin
+        R = real(elty)
+        tol = R == Float32 ? 1e-2 : 1e-5
+        ℓ = min(m, n)
+
+        B = rand(elty,m,m)
+        FB = qr(B)
+        C = rand(elty,n,n)
+        FC = qr(C)
+        Σ = zeros(R,m,n)
+        for i = 1:ℓ
+            Σ[i,i] = (10-i+1)*one(R)
+        end
+        A = FB.Q * Σ * FC.Q
+        d_A = CuMatrix(A)
+
+        d_U, d_Σ, d_V = CUSOLVER.Xgesvdr!('N', 'N', d_A, 3)
+        @test norm(diag(Σ)[1:3] - collect(d_Σ[1:3])) ≤ tol
+
+        d_U, d_Σ, d_V = CUSOLVER.Xgesvdr!('S', 'S', d_A, ℓ)
+        @test norm(diag(Σ) - collect(d_Σ)) ≤ tol
+    end
 
     @testset "syevdx!" begin
         R = real(elty)