make SparseMatrixCSC and SparseVector work on non-numerical values (#30580)

* make SparseMatrixCSC and SparseVector work on non-numerical values

* remove tests for sparse structures with TV=String as it is no longer supported

* define zero(T) and zero(x::T) for user defined types in tests

* fix test

* Remove recently added test of sparse matrix with string elements

Author: abraunst

stdlib/SparseArrays/src/sparsematrix.jl

@@ -385,7 +385,7 @@ function SparseMatrixCSC{Tv,Ti}(M::AbstractMatrix) where {Tv,Ti}
 end
 
 function SparseMatrixCSC{Tv,Ti}(M::StridedMatrix) where {Tv,Ti}
-    nz = count(t -> t != 0, M)
+    nz = count(!iszero, M)
     colptr = zeros(Ti, size(M, 2) + 1)
     nzval = Vector{Tv}(undef, nz)
     rowval = Vector{Ti}(undef, nz)
@@ -394,7 +394,7 @@ function SparseMatrixCSC{Tv,Ti}(M::StridedMatrix) where {Tv,Ti}
     @inbounds for j in 1:size(M, 2)
         for i in 1:size(M, 1)
             v = M[i, j]
-            if v != 0
+            if !iszero(v)
                 rowval[cnt] = i
                 nzval[cnt] = v
                 cnt += 1
@@ -1241,7 +1241,7 @@ Removes stored numerical zeros from `A`, optionally trimming resulting excess sp
 For an out-of-place version, see [`dropzeros`](@ref). For
 algorithmic information, see `fkeep!`.
 """
-dropzeros!(A::SparseMatrixCSC; trim::Bool = true) = fkeep!(A, (i, j, x) -> x != 0, trim)
+dropzeros!(A::SparseMatrixCSC; trim::Bool = true) = fkeep!(A, (i, j, x) -> !iszero(x), trim)
 """
     dropzeros(A::SparseMatrixCSC; trim::Bool = true)
 
@@ -2330,7 +2330,7 @@ function _setindex_scalar!(A::SparseMatrixCSC{Tv,Ti}, _v, _i::Integer, _j::Integ
     end
     # Column j does not contain entry A[i,j]. If v is nonzero, insert entry A[i,j] = v
     # and return. If to the contrary v is zero, then simply return.
-    if v != 0
+    if !iszero(v)
         insert!(A.rowval, searchk, i)
         insert!(A.nzval, searchk, v)
         @simd for m in (j + 1):(A.n + 1)
@@ -3184,7 +3184,7 @@ function is_hermsym(A::SparseMatrixCSC, check::Function)
                 # We therefore "catch up" here while making sure that
                 # the elements are actually zero.
                 while row2 < col
-                    if nzval[offset] != 0
+                    if !iszero(nzval[offset])
                         return false
                     end
                     offset += 1
@@ -3222,7 +3222,7 @@ function istriu(A::SparseMatrixCSC)
             if rowval[l1-i] <= col
                 break
             end
-            if nzval[l1-i] != 0
+            if !iszero(nzval[l1-i])
                 return false
             end
         end
@@ -3241,7 +3241,7 @@ function istril(A::SparseMatrixCSC)
             if rowval[i] >= col
                 break
             end
-            if nzval[i] != 0
+            if !iszero(nzval[i])
                 return false
             end
         end

stdlib/SparseArrays/src/sparsevector.jl

@@ -300,7 +300,7 @@ function setindex!(x::SparseVector{Tv,Ti}, v::Tv, i::Ti) where {Tv,Ti<:Integer}
     if 1 <= k <= m && nzind[k] == i  # i found
         nzval[k] = v
     else  # i not found
-        if v != 0
+        if !iszero(v)
             insert!(nzind, k, i)
             insert!(nzval, k, v)
         end
@@ -392,7 +392,7 @@ function _dense2indval!(nzind::Vector{Ti}, nzval::Vector{Tv}, s::AbstractArray{T
     c = 0
     @inbounds for i = 1:n
         v = s[i]
-        if v != 0
+        if !iszero(v)
             if c >= cap
                 cap *= 2
                 resize!(nzind, cap)
@@ -1929,7 +1929,7 @@ Removes stored numerical zeros from `x`, optionally trimming resulting excess sp
 For an out-of-place version, see [`dropzeros`](@ref). For
 algorithmic information, see `fkeep!`.
 """
-dropzeros!(x::SparseVector; trim::Bool = true) = fkeep!(x, (i, x) -> x != 0, trim)
+dropzeros!(x::SparseVector; trim::Bool = true) = fkeep!(x, (i, x) -> !iszero(x), trim)
 
 """
     dropzeros(x::SparseVector; trim::Bool = true)

stdlib/SparseArrays/test/higherorderfns.jl

@@ -287,17 +287,14 @@ end
     A, fA = sparse(1.0I, N, N), Matrix(1.0I, N, N)
     B, fB = spzeros(1, N), zeros(1, N)
     intorfloat_zeropres(xs...) = all(iszero, xs) ? zero(Float64) : Int(1)
-    stringorfloat_zeropres(xs...) = all(iszero, xs) ? zero(Float64) : "hello"
     intorfloat_notzeropres(xs...) = all(iszero, xs) ? Int(1) : zero(Float64)
-    stringorfloat_notzeropres(xs...) = all(iszero, xs) ? "hello" : zero(Float64)
-    for fn in (intorfloat_zeropres, intorfloat_notzeropres,
-                stringorfloat_zeropres, stringorfloat_notzeropres)
+    for fn in (intorfloat_zeropres, intorfloat_notzeropres)
         @test map(fn, A) == sparse(map(fn, fA))
         @test broadcast(fn, A) == sparse(broadcast(fn, fA))
         @test broadcast(fn, A, B) == sparse(broadcast(fn, fA, fB))
         @test broadcast(fn, B, A) == sparse(broadcast(fn, fB, fA))
     end
-    for fn in (intorfloat_zeropres, stringorfloat_zeropres)
+    for fn in (intorfloat_zeropres,)
         @test broadcast(fn, A, B, A) == sparse(broadcast(fn, fA, fB, fA))
     end
 end

stdlib/SparseArrays/test/sparse.jl

@@ -1263,15 +1263,16 @@ end
         @test isequal(findmax(A, dims=tup), (rval, rind))
     end
 
-    A = sparse(["a", "b"])
-    @test_throws MethodError findmin(A, dims=1)
+    # sparse arrays of types without zero(T) are forbidden
+    @test_throws MethodError sparse(["a", "b"])
 end
 
 # Support the case when user defined `zero` and `isless` for non-numerical type
 struct CustomType
     x::String
 end
 Base.zero(::Type{CustomType}) = CustomType("")
+Base.zero(x::CustomType) = zero(CustomType)
 Base.isless(x::CustomType, y::CustomType) = isless(x.x, y.x)
 @testset "findmin/findmax for non-numerical type" begin
     A = sparse([CustomType("a"), CustomType("b")])
@@ -2286,17 +2287,6 @@ end
         @test findnext(!iszero, z,i) == findnext(!iszero, z_sp,i)
         @test findprev(!iszero, z,i) == findprev(!iszero, z_sp,i)
     end
-
-    w = [ "a" ""; "" "b"]
-    w_sp = sparse(w)
-
-    for i in keys(w)
-        @test findnext(!isequal(""), w,i) == findnext(!isequal(""), w_sp,i)
-        @test findprev(!isequal(""), w,i) == findprev(!isequal(""), w_sp,i)
-        @test findnext(isequal(""), w,i) == findnext(isequal(""), w_sp,i)
-        @test findprev(isequal(""), w,i) == findprev(isequal(""), w_sp,i)
-    end
-
 end
 
 # #20711

test/hashing.jl

@@ -159,6 +159,7 @@ Base.hash(x::CustomHashReal, h::UInt) = hash(x.x, h)
 Base.:(==)(x::CustomHashReal, y::Number) = x.x == y
 Base.:(==)(x::Number, y::CustomHashReal) = x == y.x
 Base.zero(::Type{CustomHashReal}) = CustomHashReal(0.0)
+Base.zero(x::CustomHashReal) = zero(CustomHashReal)
 
 let a = sparse([CustomHashReal(0), CustomHashReal(3), CustomHashReal(3)])
     @test hash(a) == hash(Array(a))

test/show.jl

@@ -560,6 +560,9 @@ end
 
 # issue #12960
 mutable struct T12960 end
+import Base.zero
+Base.zero(::Type{T12960}) = T12960()
+Base.zero(x::T12960) = T12960()
 let
     A = sparse(1.0I, 3, 3)
     B = similar(A, T12960)