MFI calculation wrong?

[ghost]

I was testing MFI on BTCUSD daily, and noticed that investing.com, tradingview, and cryptowat.ch all return similar values, but they are different from what this library is generating.

I digged in the code, and I have a feeling there's a mistake in calculating the Typical price. Based on this:

Typical Price = (High + Low + Close)/3

But the library seems to NOT divide by 3. I tried to divide this number by 3 manually, but this did not seem to affect the results. Any idea what might be causing the disprecancy in what this library returns, and what the other websites return?

Thx!

[anandanand84]

can you give me a screenshot of tradingview comparing against https://cryptotrading-hub.com (uses this library). As for your typeical price, it does divide by 3. see the link below.

https://github.com/anandanand84/technicalindicators/blob/master/src/chart_types/TypicalPrice.ts#L23

[JMoli]

Hi Andy, make sure you enabled proper precision if you are going to use this library for crypto trading

https://github.com/anandanand84/technicalindicators#precision

[anandanand84]

The test case for MFI is based on the stock charts link you provided https://github.com/anandanand84/technicalindicators/blob/master/test/volume/MFI.js and the test pass so either the calculation provided in the stockcharts is wrong or it should be wrong in the other websites. If you think stock charts is wrong then we may need the actual logic to fix.

[ghost]

There we go. As you can see, I hovered over the same candles, and the MFI values are not the same. You can also notice that the MFI value before we reach 20k hits 100 on tradingview, but to 87 on this library.

[JMoli]

Are the inputs the same? I can see a value of 14 on one but not the other

[anandanand84]

@andyperisho Thanks for taking the time to get the screenshot. Agreed there is a bug and I looked the code and figured out where the bug is. One last thing can you get me values of high, low, close and the mfi for me to write the test case. Currently this library compares the typical price against close which should be against previous typical price, can you get me the test case so I could make the fix.

[ghost]

@JMoli yes they are the same. It's BTC/USDT for binance, so i doubt they would differ :)

@anandanand84 I see u closed the issue. So is this resolved, or do u still need the information u requested?

[anandanand84]

It is resolved, but you check again and confirm.

[ghost]

Could u publish it to npm?

[anandanand84]

it is published

[ghost]

npm ERR! code ETARGET
npm ERR! notarget No matching version found for technicalindicators@^1.1.11

[ghost]

And on npm, looks like it's still at 1.1.10: https://www.npmjs.com/package/technicalindicators

[anandanand84]

Sorry my bad I thought I published it. Published now.

[ghost]

Confirmed and tested. The results match what i'm seeing on trading view. Thx a lot mate.

I'm curious, did the change impact the tests u had from the traditional market data?

[anandanand84]

The problem was the test from the stockcharts.com had computation from typical price and not from high, low, close. So I manually created high, low, close to to the same value to get the same typical price. So in my test case typical price and close had the same value so it passed when I compared it with the prev close instead of prev typical price since because both are same.

https://github.com/anandanand84/technicalindicators/blob/master/test/volume/MFI.js#L11

[ghost]

That makes sense.

In any case, thank you very much for your swift response!