7 SUBROUTINE splaan (N, X, Y, B, C, D)
9 REAL X(N), Y(N), B(N), C(N), D(N)
44 IF ( n .LT. 2 )
RETURN
45 IF ( n .LT. 3 )
GO TO 50
52 c(2) = (y(2) - y(1))/d(1)
55 b(i) = 2.*(d(i-1) + d(i))
56 c(i+1) = (y(i+1) - y(i))/d(i)
67 IF ( n .EQ. 3 )
GO TO 15
68 c(1) = (y(2)-y(1))/d(1)
69 c(n) = c(n-1)/(x(n)-x(n-2)) - c(n-2)/(x(n-1)-x(n-3))
70 c(n) = -c(n)*d(n-1)**2/(x(n)-x(n-3))
76 b(i) = b(i) - t*d(i-1)
77 c(i) = c(i) - t*c(i-1)
85 c(i) = (c(i) - d(i)*c(i+1))/b(i)
92 b(n) = (y(n) - y(nm1))/d(nm1) + d(nm1)*(c(nm1) + 2.*c(n))
94 b(i) = (y(i+1) - y(i))/d(i) - d(i)*(c(i+1) + 2.*c(i))
95 d(i) = (c(i+1) - c(i))/d(i)
102 50 b(1) = (y(2)-y(1))/(x(2)-x(1))