Data update

Task/Multiple-regression/QB64/multiple-regression.qb64

@@ -0,0 +1,71 @@
+Const N = 14, M = 2, Q = 3 ' number of points and M.R. polynom degree
+
+Dim X(N) As Double ' data points
+Data 1.47,1.50,1.52,1.55,1.57,1.60,1.63,1.65,1.68,1.70,1.73,1.75,1.78,1.80,1.83
+For c = LBound(X) To UBound(X)
+    Read X(c)
+Next c
+Dim As Double Y(N) ' data points
+Data 52.21,53.12,54.48,55.84,57.20,58.57,59.93,61.29,63.11,64.47,66.28,68.10,69.92,72.19,74.46
+For c = LBound(Y) To UBound(Y)
+    Read Y(c)
+Next c
+Dim As Double S(N), T(N) ' linear system coefficient
+Dim As Double A(M, Q)    ' system to be solved
+Dim As Integer i, k, j, fila, columna
+Dim As Double z
+
+For k = 0 To 2 * M
+    S(k) = 0: T(k) = 0
+    For i = 0 To N
+        S(k) = S(k) + X(i) ^ k
+        If k <= M Then T(k) = T(k) + Y(i) * X(i) ^ k
+    Next i
+Next k
+
+' build linear system
+For fila = 0 To M
+    For columna = 0 To M
+        A(fila, columna) = S(fila + columna)
+    Next columna
+    A(fila, columna) = T(fila)
+Next fila
+
+Print "Linear system coefficents:"
+For i = 0 To M
+    For j = 0 To M + 1
+        Print Using "######.#"; A(i, j);
+    Next j
+    Print
+Next i
+
+For j = 0 To M
+    For i = j To M
+        If A(i, j) <> 0 Then Exit For
+    Next i
+    If i = M + 1 Then
+        Print: Print "SINGULAR MATRIX '"
+        End
+    End If
+    For k = 0 To M + 1
+        Swap A(j, k), A(i, k)
+    Next k
+    z = 1 / A(j, j)
+    For k = 0 To M + 1
+        A(j, k) = z * A(j, k)
+    Next k
+    For i = 0 To M
+        If i <> j Then
+            z = -A(i, j)
+            For k = 0 To M + 1
+                A(i, k) = A(i, k) + z * A(j, k)
+            Next k
+        End If
+    Next i
+Next j
+
+Print: Print "Solutions:"
+For i = 0 To M
+    Print Using "  #####.#######"; A(i, M + 1);
+Next i
+End