Option Explicit On
Option Strict On
Public Class Form4
    Private KTE As Integer = 20000
    Private KTJ As Integer = 20000
    Private KED As Integer = 20000
    Private KCM As Integer = 100


    Private Sub Form4_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Call SQRELOCA()
        Me.Close()
    End Sub


    Private Sub SQRELOCA()
        Dim NODE As Integer
        Dim NELM As Integer
        Dim mtj(,) As Integer
        Dim px() As Double
        Dim py() As Double
        Dim ifix() As Integer

        ReDim mtj(KTE, 4)
        ReDim px(KTJ)
        ReDim py(KTJ)
        ReDim ifix(KTJ)

        Call SQINPUT(NELM, NODE, mtj, px, py, ifix)
        Call SQLAPLAS(NELM, NODE, mtj, px, py, ifix)
        Call SQDATA(NELM, NODE, mtj, px, py, ifix)

    End Sub


    Private Sub SQINPUT(ByRef NELM As Integer, ByRef NODE As Integer, ByRef mtj(,) As Integer, _
                        ByRef px() As Double, ByRef py() As Double, ByRef ifix() As Integer)

        Dim sr As System.IO.StreamReader
        Dim dat As String
        Dim sbuf() As String
        Dim delim() As Char = {","c}
        Dim fname1 As String
        Dim i As Integer
        Dim j As Integer

        fname1 = My.Forms.Form1.Label1.Text
        fname1 = System.IO.Path.GetDirectoryName(fname1)
        fname1 = fname1 & "\workf3.csv"
        sr = New System.IO.StreamReader(fname1, System.Text.Encoding.Default)
        dat = sr.ReadLine() : sbuf = dat.Split(delim)
        NODE = CInt(sbuf(0))
        NELM = CInt(sbuf(1))
        For i = 1 To NELM
            dat = sr.ReadLine() : sbuf = dat.Split(delim)
            For j = 1 To 4
                mtj(i, j) = CInt(sbuf(j - 1))
        Next j, i
        For i = 1 To NODE
            dat = sr.ReadLine() : sbuf = dat.Split(delim)
            px(i) = CDbl(sbuf(0))
            py(i) = CDbl(sbuf(1))
            ifix(i) = CInt(sbuf(2))
        Next i
        sr.Close()

    End Sub


    Private Sub SQLAPLAS(ByRef NELM As Integer, ByRef NODE As Integer, ByRef mtj(,) As Integer, _
                         ByRef px() As Double, ByRef py() As Double, ByRef ifix() As Integer)
        Dim i As Integer
        Dim j As Integer
        Dim k As Integer
        Dim l As Integer
        Dim ja As Integer
        Dim jb As Integer
        Dim ip As Integer
        Dim ix As Integer
        Dim ka As Integer
        Dim kb As Integer
        Dim la As Integer
        Dim lb As Integer
        Dim itera As Integer
        Dim it As Integer
        Dim j1 As Integer
        Dim j2 As Integer
        Dim j3 As Integer
        Dim j4 As Integer
        Dim ielm As Integer

        Dim gx As Double
        Dim gy As Double
        Dim ar As Double
        Dim s As Double
        Dim xc As Double
        Dim yc As Double
        Dim cgrax As Double
        Dim cgray As Double

        Dim jac(,) As Integer
        Dim ihen(,) As Integer
        Dim jhen() As Integer
        Dim khen() As Integer
        Dim jnb() As Integer
        Dim nei(,) As Integer

        ReDim jac(KED, 4)
        ReDim ihen(KED, 2)
        ReDim jhen(KED)
        ReDim khen(KED)
        ReDim jnb(KED)
        ReDim nei(KED, KCM)

        For i = 1 To KTE
            For j = 1 To 4
                jac(i, j) = 0
        Next j, i

        ix = 0
        For i = 1 To KED
            ihen(i, 1) = 0
            ihen(i, 2) = 0
            jhen(i) = 0
            khen(i) = 0
        Next i

        For i = 1 To KTJ
            jnb(i) = 0
            For j = 1 To KCM
                nei(i, j) = 0
        Next j, i

        For j = 1 To NELM
            For k = 1 To 4
                ka = mtj(j, k)
                kb = mtj(j, (k Mod 4) + 1)
                For l = 1 To ix
                    la = ihen(l, 1)
                    lb = ihen(l, 2)
                    If (ka = lb) And (kb = la) Then GoTo sqlaplas70
                Next l
                ix = ix + 1
                ihen(ix, 1) = ka
                ihen(ix, 2) = kb
                jhen(ix) = j
                khen(ix) = k
                GoTo sqlaplas50

sqlaplas70:
                jac(j, k) = jhen(l)
                jac(jhen(l), khen(l)) = j
sqlaplas50:
        Next k, j

        For i = 1 To NELM
            For j = 1 To 4
                If jac(i, j) = 0 Then
                    ja = mtj(i, j)
                    jb = mtj(i, (j Mod 4) + 1)
                    ifix(ja) = 1
                    ifix(jb) = 1
                End If
        Next j, i

        For i = 1 To NELM
            For j = 1 To 4
                ip = mtj(i, j)
                jnb(ip) = jnb(ip) + 1
                nei(ip, jnb(ip)) = i
        Next j, i

        itera = 5
        For it = 1 To itera
            For i = 1 To NODE
                If ifix(i) = 0 Then
                    gx = 0.0
                    gy = 0.0
                    ar = 0.0
                    For j = 1 To jnb(i)
                        ielm = nei(i, j)
                        j1 = mtj(ielm, 1)
                        j2 = mtj(ielm, 2)
                        j3 = mtj(ielm, 3)
                        j4 = mtj(ielm, 4)
                        s = SQAREA(ielm, mtj, px, py)
                        xc = (px(j1) + px(j2) + px(j3) + px(j4)) / 4.0
                        yc = (py(j1) + py(j2) + py(j3) + py(j4)) / 4.0
                        ar = ar + s
                        gx = gx + s * xc
                        gy = gy + s * yc
                    Next j
                    cgrax = gx / ar
                    cgray = gy / ar
                    px(i) = cgrax
                    py(i) = cgray
                End If
            Next i
        Next it

    End Sub


    Private Function SQAREA(ByRef ielm As Integer, ByRef mtj(,) As Integer, ByRef px() As Double, ByRef py() As Double) As Double
        Dim j1 As Integer
        Dim j2 As Integer
        Dim j3 As Integer
        Dim j4 As Integer
        Dim area1 As Double
        Dim area2 As Double

        j1 = mtj(ielm, 1)
        j2 = mtj(ielm, 2)
        j3 = mtj(ielm, 3)
        j4 = mtj(ielm, 4)
        area1 = 0.5 * (px(j1) * py(j2) + px(j2) * py(j3) + px(j3) * py(j1) - px(j1) * py(j3) - px(j2) * py(j1) - px(j3) * py(j2))
        area2 = 0.5 * (px(j1) * py(j3) + px(j3) * py(j4) + px(j4) * py(j1) - px(j1) * py(j4) - px(j3) * py(j1) - px(j4) * py(j3))
        SQAREA = area1 + area2

    End Function


    Private Sub SQDATA(ByRef NELM As Integer, ByRef NODE As Integer, ByRef mtj(,) As Integer, _
                       ByRef px() As Double, ByRef py() As Double, ByRef ifix() As Integer)
        Dim sw As System.IO.StreamWriter
        Dim dat As String
        Dim fname2 As String
        Dim i As Integer

        fname2 = My.Forms.Form1.Label2.Text
        sw = New System.IO.StreamWriter(fname2, False, System.Text.Encoding.Default)
        dat = NODE.ToString & "," & NELM.ToString : sw.WriteLine(dat)
        For i = 1 To NELM
            dat = mtj(i, 1).ToString & "," & mtj(i, 2).ToString & "," & mtj(i, 3).ToString & "," & mtj(i, 4).ToString
            sw.WriteLine(dat)
        Next i
        For i = 1 To NODE
            dat = px(i).ToString("0.000") & "," & py(i).ToString("0.000")
            sw.WriteLine(dat)
        Next i
        sw.Close()

    End Sub

End Class