Revert "Scaling for partly initialized unit triangular"

This reverts commit 28c8eca.

Author: jishnub

src/triangular.jl

@@ -1323,6 +1323,15 @@ end
 # Generic routines #
 ####################
 
+function _set_diag!(B::UpperOrLowerTriangular, x)
+    # get a mutable array to modify the diagonal
+    Bm = parent(B) isa StridedArray ? B : copy!(similar(B), B)
+    for i in diagind(Bm.data, IndexStyle(Bm.data))
+        Bm.data[i] = x
+    end
+    Bm
+end
+
 for (t, unitt) in ((UpperTriangular, UnitUpperTriangular),
                    (LowerTriangular, UnitLowerTriangular))
     tstrided = t{<:Any, <:StridedMaybeAdjOrTransMat}
@@ -1335,8 +1344,8 @@ for (t, unitt) in ((UpperTriangular, UnitUpperTriangular),
         end
 
         function (*)(A::$unitt, x::Number)
-            B = copy!(similar($t(A.data)), A)
-            B * x
+            B = $t(A.data)*x
+            _set_diag!(B, oneunit(eltype(A)) * x)
         end
 
         (*)(x::Number, A::$t) = $t(x*A.data)
@@ -1347,8 +1356,8 @@ for (t, unitt) in ((UpperTriangular, UnitUpperTriangular),
         end
 
         function (*)(x::Number, A::$unitt)
-            B = copy!(similar($t(A.data)), A)
-            x * B
+            B = x*$t(A.data)
+            _set_diag!(B, x * oneunit(eltype(A)))
         end
 
         (/)(A::$t, x::Number) = $t(A.data/x)
@@ -1359,8 +1368,8 @@ for (t, unitt) in ((UpperTriangular, UnitUpperTriangular),
         end
 
         function (/)(A::$unitt, x::Number)
-            B = copy!(similar($t(A.data)), A)
-            B / x
+            B = $t(A.data)/x
+            _set_diag!(B, oneunit(eltype(A)) / x)
         end
 
         (\)(x::Number, A::$t) = $t(x\A.data)
@@ -1371,8 +1380,8 @@ for (t, unitt) in ((UpperTriangular, UnitUpperTriangular),
         end
 
         function (\)(x::Number, A::$unitt)
-            B = copy!(similar($t(A.data)), A)
-            x \ B
+            B = x\$t(A.data)
+            _set_diag!(B, x \ oneunit(eltype(A)))
         end
     end
 end

test/triangular.jl

@@ -944,18 +944,4 @@ end
     @test 2*U == 2*M
 end
 
-@testset "scaling partly initialized unit triangular" begin
-    for T in (UnitUpperTriangular, UnitLowerTriangular)
-        isupper = T == UnitUpperTriangular
-        M = Matrix{BigFloat}(undef,2,2)
-        M[1+!isupper, 1+isupper] = 3
-        U = T(M)
-        C = Matrix(U)
-        @test U * 2 == C * 2
-        @test 2 * U == 2 * C
-        @test U / 2 == C / 2
-        @test 2 \ U == 2 \ C
-    end
-end
-
 end # module TestTriangular