Ignore 1-sized dimension during vector layout check.

Close #44497

stdlib/LinearAlgebra/src/blas.jl

@@ -149,9 +149,22 @@ end
 # A help function to pick the pointer and inc for 1d like inputs.
 @inline function vec_pointer_stride(x::AbstractArray, stride0check = nothing)
     isdense(x) && return pointer(x), 1 # simpify runtime check when possibe
-    ndims(x) == 1 || strides(x) == Base.size_to_strides(stride(x, 1), size(x)...) ||
-        throw(ArgumentError("only support vector like inputs"))
-    st = stride(x, 1)
+    if ndims(x) <= 1
+        st = stride(x, 1)
+    else
+        sts, szs = strides(x), size(x)
+        i = 0
+        while i < ndims(x) && szs[i+=1] == 1 end # skip 1-sized dimension.
+        st = sts[i]
+        stᵢ = st
+        while i < ndims(x)
+            i += 1
+            stᵢ *= szs[i-1]
+            if szs[i] != 1
+                stᵢ == sts[i] || throw(ArgumentError("only support vector like inputs"))
+            end
+        end
+    end
     isnothing(stride0check) || (st == 0 && throw(stride0check))
     ptr = st > 0 ? pointer(x) : pointer(x, lastindex(x))
     ptr, st

stdlib/LinearAlgebra/test/blas.jl

@@ -18,9 +18,14 @@ function pack(A, uplo)
 end
 
 @testset "vec_pointer_stride" begin
-    a = zeros(4,4,4)
-    @test BLAS.asum(view(a,1:2:4,:,:)) == 0 # vector like
+    a = float(rand(1:20,4,4,4))
+    @test BLAS.asum(a) == sum(a) # dense case
+    @test BLAS.asum(view(a,1:2:4,:,:)) == sum(view(a,1:2:4,:,:)) # vector like
+    @test BLAS.asum(view(a,1:3,2:2,3:3)) == sum(view(a,1:3,2:2,3:3))
+    @test BLAS.asum(view(a,1:1,1:3,1:1)) == sum(view(a,1:1,1:3,1:1))
+    @test BLAS.asum(view(a,1:1,1:1,1:3)) == sum(view(a,1:1,1:1,1:3))
     @test_throws ArgumentError BLAS.asum(view(a,1:3:4,:,:)) # non-vector like
+    @test_throws ArgumentError BLAS.asum(view(a,1:2,1:1,1:3))
 end
 Random.seed!(100)
 ## BLAS tests - testing the interface code to BLAS routines