Implementing LAPACK routine hseqr() in Julia (creating wrapper error: no method matching Array{Float64,1}(::Int64))

Question

我正在尝试实现从 LAPACK(link:http://www.netlib.org/lapack/explore-html/da/dba/group__double_o_t_h_e_rcomputational_gacb35e85b362ce8ccf9d653cc3f8fb89c.html#gacb35e85b362ce8ccf9d653cc3f8fb89c) 到 Julia 的 hseqr() 例程，但是当我调用该函数时出现此错误：

error: no method matching Array{Float64,1}(::Int64)

这是我的代码：

for (hseqr, elty) in
    ((:dhseqr_,:Float64),
    (:shseqr_,:Float32))
    @eval begin
        """
     JOB    
          JOB is CHARACTER*1
           = 'E':  compute eigenvalues only;
           = 'S':  compute eigenvalues and the Schur form T.
    COMPZ   
          COMPZ is CHARACTER*1
           = 'N':  no Schur vectors are computed;
           = 'I':  Z is initialized to the unit matrix and the matrix Z
                   of Schur vectors of H is returned;
           = 'V':  Z must contain an orthogonal matrix Q on entry, and
                   the product Q*Z is returned.
        """
        function hseqr!(job::Char,compz::Char,ilo::Integer,ihi::Integer,H::StridedMatrix{$elty}, Z::StridedMatrix{$elty})
            N=size(H,1)
            ldh=size(H,1)
            ldz=size(Z,1)
            work = Vector{$elty}(1)
            lwork = BlasInt(-1)
            info = Ref{BlasInt}()
            for i = 1:2  # first call returns lwork as work[1]
                ccall((@blasfunc($hseqr), liblapack),Void,
                    (Ref{UInt8},Ref{UInt8}, Ref{BlasInt},Ref{BlasInt},Ref{BlasInt},
                        Ptr{$elty}, Ref{BlasInt},Ptr{$elty}, Ptr{$elty}, Ptr{$elty}, 
                        Ref{BlasInt}, Ptr{BlasInt}, Ref{BlasInt}, Ref{BlasInt}),
                        job,compz, N,ilo,ihi,H,ldh,wr,wi,Z,ldz,work, 
                        lwork,info) 
                chklapackerror(info[])
                if i == 1
                    lwork = BlasInt(real(work[1]))
                    resize!(work, lwork)
                end
            end
            return wr,wi,Z
        end
    end
end
hseqr!(job::Char,compz::Char,H::StridedMatrix{},Z::StridedMatrix{}) = hseqr!(job,compz,1, size(H, 1), H,Z)

这是我的电话： hseqr!('E','N',H,Matrix{Float64}(I,5,5))（H 是维数为 5 的 Hessenberg 矩阵）。

我不确定我是否正确理解如何制作包装纸，所以任何提示都有帮助。

Answer 1

这是一个很好的问题示例，可以从中剥离相当多的内容以隔离问题。

如果我正确阅读你的代码，行

work = Vector{$elty}(1)

以 Float64 作为元素类型调用，所以整个事情归结为：

julia> Vector{Float64}(1)
ERROR: MethodError: no method matching Array{Float64,1}(::Int64)

您滥用了向量的构造函数。现在我不确定你想在这里做什么，但如果你想创建一个长度为 1 的 Float64 数字的向量，你可能正在寻找以下之一：

julia> Array{Float64}(undef, 1)
1-element Array{Float64,1}:
 6.9274314537094e-310

julia> zeros(1)
1-element Array{Float64,1}:
 0.0

请注意，第一次调用使数组未初始化，即它被之前内存中的任何内容填充，因此您要确保仅在稍后实际覆盖它时才使用它。

Implementing LAPACK routine hseqr() in Julia (creating wrapper error: no method matching Array{Float64,1}(::Int64))

Implementing LAPACK routine hseqr() in Julia (creating wrapper error: no method matching Array{Float64,1}(::Int64))

linear-algebra

eigenvalue

lapack

julia