milank
01-12-2004, 03:35 PM
I am wondering if there is a bug in the spline routine. Specifically,
when using the ypn input parameter to specify the second derivative for the last point in the table when ypn is, say, 2 ( like for f(x) = x^2), the value y2[n-1] is not equal to ypn. On the other hand, y2[0] is very close to yp1 (e.g., for yp1=2). As I understand, y2[0] to y2[n-1] should be the second derivatives
for the points in the table, so I would expect that y2[0]=yp1 and
y2[n-1] = ypn unless I am doing a natural cubic spline (i.e., second
derivatives are zero's at the boundaries).
Milan
when using the ypn input parameter to specify the second derivative for the last point in the table when ypn is, say, 2 ( like for f(x) = x^2), the value y2[n-1] is not equal to ypn. On the other hand, y2[0] is very close to yp1 (e.g., for yp1=2). As I understand, y2[0] to y2[n-1] should be the second derivatives
for the points in the table, so I would expect that y2[0]=yp1 and
y2[n-1] = ypn unless I am doing a natural cubic spline (i.e., second
derivatives are zero's at the boundaries).
Milan