qcksrt.txt

VB常用数值算法集 内含有解线性代数方程组

Sub QCKSRT(N, ARR())
    M = 7: NSTACK = 50: FM = 7875: FA = 211: FC = 1663: FMI = 0.00012698413
    Dim ISTACK(50)
    JSTACK = 0
    L = 1
    IR = N
    FX = 0
    Do
      If IR - L < M Then
          For J = L + 1 To IR
              A = ARR(J)
              For I = J - 1 To 1 Step -1
                  If ARR(I) <= A Then Exit For
                  ARR(I + 1) = ARR(I)
              Next I
              If ARR(I) = 0 Then I = 0
              ARR(I + 1) = A
          Next J
          If JSTACK = 0 Then Exit Sub
          IR = ISTACK(JSTACK)
          L = ISTACK(JSTACK - 1)
          JSTACK = JSTACK - 2
      Else
          I = L
          J = IR
          FX = FX * FA + FC - FM * Int((FX * FA + FC) / FM)
          IQ = L + (IR - L + 1) * (FX * FMI)
          A = ARR(IQ)
          ARR(IQ) = ARR(L)
          Do
            Do
              If J > 0 Then
                If A < ARR(J) Then
                    J = J - 1
                    DONE% = 0
                Else
                    DONE% = -1
                End If
              End If
            Loop While Not DONE%
            If J <= I Then
                ARR(I) = A
                Exit Do
            End If
            ARR(I) = ARR(J)
            I = I + 1
            Do
              If I <= N Then
                If A > ARR(I) Then
                  I = I + 1
                  DONE% = 0
                Else
                  DONE% = -1
                End If
              End If
            Loop While Not DONE%
            If J <= I Then
              ARR(J) = A
              I = J
              Exit Do
            End If
            ARR(J) = ARR(I)
            J = J - 1
          Loop
          JSTACK = JSTACK + 2
          If JSTACK > NSTACK Then Print "NSTACK must be made larger.": Exit Sub
          If IR - I >= I - L Then
              ISTACK(JSTACK) = IR
              ISTACK(JSTACK - 1) = I + 1
              IR = I - 1
          Else
              ISTACK(JSTACK) = I - 1
              ISTACK(JSTACK - 1) = L
              L = I + 1
          End If
      End If
    Loop
End Sub