Fix infQR for upper triangular (#9)

* Fix infQR for upper triangular

* Update test_infqr.jl

* v0.1.1

Author: dlfivefifty

Project.toml

@@ -1,6 +1,6 @@
 name = "InfiniteLinearAlgebra"
 uuid = "cde9dba0-b1de-11e9-2c62-0bab9446c55c"
-version = "0.1"
+version = "0.1.1"
 
 [deps]
 ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"

src/InfiniteLinearAlgebra.jl

@@ -16,7 +16,7 @@ import LinearAlgebra: lmul!,  ldiv!, matprod, qr, AbstractTriangular, AbstractQ,
 import LazyArrays: applybroadcaststyle, CachedArray, CachedMatrix, CachedVector, DenseColumnMajor, FillLayout, ApplyMatrix, check_mul_axes, ApplyStyle, LazyArrayApplyStyle, LazyArrayStyle,
                     CachedMatrix, CachedArray, resizedata!, MemoryLayout, mulapplystyle, LmulStyle, RmulStyle,
                     factorize, sub_materialize, LazyLayout, LazyArrayStyle,
-                    @lazymul, applylayout, ApplyLayout, PaddedLayout, materialize!
+                    @lazymul, applylayout, ApplyLayout, PaddedLayout, materialize!, zero!
 import MatrixFactorizations: ql, ql!, QLPackedQ, getL, getR, reflector!, reflectorApply!, QL, QR, QRPackedQ
 
 import BlockArrays: BlockSizes, cumulsizes, _find_block, AbstractBlockVecOrMat, sizes_from_blocks

src/infqr.jl

@@ -18,13 +18,17 @@ function partialqr!(F::AdaptiveQRData{<:Any,<:BandedMatrix}, n::Int)
         resizedata!(F.data,n+l,n+u+l);
         resize!(F.τ,n);
         ñ = F.ncols
-        factors = view(F.data.data,ñ+1:n+l,ñ+1:n);
         τ = view(F.τ,ñ+1:n);
-        _banded_qr!(factors, τ);
-        # multiply remaining columns
-        n̄ = max(ñ+1,n-l-u+1) # first column interacting with extra data
-        Q = QRPackedQ(view(F.data.data,n̄:n+l,n̄:n), view(F.τ,n̄:n))
-        lmul!(Q',view(F.data.data,n̄:n+l,n+1:n+u+l))
+        if l ≤ 0 
+            zero!(τ)
+        else
+            factors = view(F.data.data,ñ+1:n+l,ñ+1:n);
+            _banded_qr!(factors, τ);
+            # multiply remaining columns
+            n̄ = max(ñ+1,n-l-u+1) # first column interacting with extra data
+            Q = QRPackedQ(view(F.data.data,n̄:n+l,n̄:n), view(F.τ,n̄:n))
+            lmul!(Q',view(F.data.data,n̄:n+l,n+1:n+u+l))
+        end
         F.ncols = n
     end
     F

test/test_infqr.jl

@@ -125,4 +125,11 @@ import InfiniteLinearAlgebra: partialqr!, AdaptiveQRData, AdaptiveLayout
         @time x = qr(AB) \ b;
         @test x[1:300] ≈ AB[1:300,1:300] \ b[1:300]
     end
+
+    @testset "triangular infqr" begin
+        A = BandedMatrix(0 => 1:∞, 2 => Ones(∞))
+        F = qr(A)
+        @test F.Q[1:10,1:10] == Eye(10)
+        @test F.R[1:10,1:10] == A[1:10,1:10]
+    end
 end