# DerivativeFilter[] is scaling down the data by ~100 or so, not a true differentiation? [duplicate]

I'm running the following function

 vzz = DerivativeFilter[z["Path"][[All, 2]], {1}];


But if I then integrate vzz the output z is about 100 smaller than the original z.

Why is this so? I thought DerivativeFilter would provide an alternative to a finite difference scheme but the magnitude of the output is just wrong.

• If you read the docs for DerivativeFilter, you will see that it applies a spline interpolation and an optional Gaussian-like filter to the data, so it is not really much like a direct finite difference. – bill s Feb 10 '16 at 20:47
• Try DerivativeFilter[{{a, b}, {c, d}}, {1}] – Dr. belisarius Feb 10 '16 at 21:19
• Potentially related: mathematica.stackexchange.com/q/85212/280 – Alexey Popkov Feb 11 '16 at 7:35
• Confirmed as a bug in this answer: (85214) – Mr.Wizard Feb 14 '16 at 16:06
• thanks guys! I guess we'll have to wait for an update. – MD Coen Feb 16 '16 at 16:14