Fix linear indexing of PDiagMat and ScalMat

Author: devmotion

src/pdiagmat.jl

@@ -31,7 +31,10 @@ LinearAlgebra.cholesky(a::PDiagMat) = cholesky(Diagonal(a.diag))
 ### Inheriting from AbstractMatrix
 
 Base.size(a::PDiagMat) = (a.dim, a.dim)
-Base.getindex(a::PDiagMat{T},i::Integer) where {T} = i % a.dim == (i ÷ a.dim + 1) ? a.diag[i % a.dim] : zero(T)
+function Base.getindex(a::PDiagMat, i::Integer)
+    ncol, nrow = fldmod1(i, a.dim)
+    ncol == nrow ? a.diag[nrow] : zero(eltype(a))
+end
 Base.getindex(a::PDiagMat{T},i::Integer,j::Integer) where {T} = i == j ? a.diag[i] : zero(T)
 
 ### Arithmetics

src/scalmat.jl

@@ -23,7 +23,10 @@ LinearAlgebra.cholesky(a::ScalMat) = cholesky(Diagonal(fill(a.value, a.dim)))
 ### Inheriting from AbstractMatrix
 
 Base.size(a::ScalMat) = (a.dim, a.dim)
-Base.getindex(a::ScalMat{T}, i::Integer) where {T} = i%a.dim == (i ÷ a.dim + 1) ? a.value : zero(T)
+function Base.getindex(a::ScalMat, i::Integer)
+    ncol, nrow = fldmod1(i, a.dim)
+    ncol == nrow ? a.value : zero(eltype(a))
+end
 Base.getindex(a::ScalMat{T}, i::Integer, j::Integer) where {T} = i == j ? a.value : zero(T)
 
 ### Arithmetics