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Dim Plt As New PyPlot

Function Pi() As Double
    Pi = 4 * Atn(1)
End Function

Sub Linspace(A As Double, B As Double, N As Long, X() As Double)
    Dim I As Long
    For I = 0 To N - 1
        X(I) = A + I * ((B - A) / (N - 1))
    Next
End Sub

Sub MeshGrid(Nx As Long, Ny As Long, Vx() As Double, Vy() As Double, X() As Double, Y() As Double)
    Dim I As Long, J As Long
    For I = 0 To Ny - 1
        For J = 0 To Nx - 1
            X(I, J) = Vx(J)
            Y(I, J) = Vy(I)
        Next
    Next
End Sub

Sub MeshGrid3(Nx As Long, Ny As Long, Nz As Long, Vx() As Double, Vy() As Double, Vz() As Double, X() As Double, Y() As Double, Z() As Double)
    Dim I As Long, J As Long, K As Long
    For I = 0 To Ny - 1
        For J = 0 To Nx - 1
            For K = 0 To Nz - 1
                X(I, J, K) = Vx(J)
                Y(I, J, K) = Vy(I)
                Z(I, J, K) = Vz(K)
            Next
        Next
    Next
End Sub

Function NARange(A As Double, B As Double, Delta As Double) As Long
    NARange = CLng((B - A) / Delta)
End Function

Sub ARange(A As Double, B As Double, Delta As Double, X() As Double)
    Dim N As Long, I As Long
    N = NARange(A, B, Delta)
    For I = 0 To N - 1
        X(I) = A + I * Delta
    Next
End Sub