Word / Эйлер

'Модифицированный метод Эйлера

Private Sub CommandButton1_Click()

Dim a, b, n, h, x0, y0, x1, y1, st, x, y, FF As Single

a = InputBox("Введи a", "Ввод", -2.15)

b = InputBox("Введи b", "Ввод", 3.97)

n = InputBox("Введи n", "Ввод", 4)

x0 = InputBox("Введи a", "Ввод", a)

y0 = InputBox("Введи y0", "Ввод", 2.662)

Cells(1, 1) = "x"

Cells(1, 2) = "y"

Cells(1, 3) = "f(x,y)"

Cells(1, 4) = "h*f(x,y)"

h = (b - a) / n

y = y0

x = x0

st = 1

For n = 1 To 4

If x <= b Then

FF = f(x, y)

x1 = x + h / 2

y1 = y + h * FF / 2

y = y + h * f(x1, y1)

x = x + h

Cells(st + 1, 1) = x

Cells(st + 1, 2) = y

Cells(st + 1, 3) = f(x, y)

Cells(st + 1, 4) = h * f(x, y)

st = st + 1

End If

Next n

End Sub

Public Function f(xx As Variant, yy As Variant)

f = -2.508 * yy + 0.617 * xx / yy + 1.418 * xx + 2.136

End FuOption Explicit

Метод простых итераций

Sub iterathii()

Dim n As Byte, a!(), c!(), b!(), eps!, d!(), s!, z!(), x!(), i As Byte, j As Byte, norma_c!(), w!(), r!

n = InputBox("Введите количество уравнений", "Ввод данных")

ReDim a(n, n + 1), c(n, n), b(n), d(n), z(n), x(n), norma_c(n), w(n)

eps = InputBox("Введите точность е", "Ввод данных")

For i = 1 To n

For j = 1 To n

a(i, j) = InputBox("Введите коэффициэнты системы при х", "Ввод данных")

Cells(i, j) = a(i, j)

Next j

b(i) = InputBox("Введите коэффициэнт без х", "Ввод данных")

Cells(i, n + 1) = "="

Cells(i, n + 2) = b(i)

Next i

For i = 1 To n

For j = 1 To n

c(i, j) = -a(i, j) / a(i, i)

Cells(i + n + 1, j) = c(i, j)

Next j

c(i, i) = 0: d(i) = b(i) / a(i, i)

Cells(i + n + 1, i) = c(i, i)

Next i

norma_c(n) = 0

For i = 1 To n

For j = 1 To n

norma_c(i) = norma_c(i) + Abs(c(i, j))

Next j

Next i

s = norma_c(1)

For i = 2 To n

If s < norma_c(i) Then

s = norma_c(i)

End If

Next i

Cells(2 * n + 3, 1) = "||c|| = "

Cells(2 * n + 3, 2) = s

If s > 1 Then

Cells(1, 1) = "Внимание! Условие сходимости не выполняется!"

Exit Sub

End If

For i = 1 To n

z(i) = d(i)

Next i

r = 1

Do

For i = 1 To n

x(i) = 0

For j = 1 To n

x(i) = x(i) + c(i, j) * z(j)

Next j

Next i

For i = 1 To n

x(i) = x(i) + d(i)

w(i) = Abs(x(i) - z(i))

Next i

r = w(1)

For i = 2 To n

If r < w(i) Then

r = w(i)

End If

Next i

For i = 1 To n

z(i) = x(i)

Next i

Loop Until r < eps

For i = 1 To n

Cells(2 * n + 3, 4) = "x(i)"

Cells(i + 2 * n + 3, 4) = z(i)

Next i

End Subnction-