I think chess.com computer got this one wrong

I think chess.com's computer's got this one wrong!  the screen shot (I will insert the game in the next post if it is not clear) shows me taking advantage of my knight's fork of White's queen and castle, and taking the castle.  This is deemed a blunder?  I should have taken white's bishop?  I will insert the game in the next post; as soon as I was a rook up, I simply began making forced trades, opening up the board to my one rook advantage, using a promotion (with a rook right behind) to get to rooks up, and finish white  off. . . let's see if anyone can explain the computer's reasoning here!

and can anyone tell me how to annotate the pgn? 

I am no expert, but from a "points" perspective, taking the bishop would have been better I think.

      You took the rook (5 points) with your knight (3 points) but you then lost the knight. 5-3=2,.so you gained two points.

      If you took the bishop (also 3 points) instead, your knight would have survived, and also you would have forced opponent to move the queen.

So the computer says 3 points is better than two.  I suppose so.  i don't think the algorithimns (sp?) factor in the ultimate power of the castle as the files open up . . . . certainly one can induce a player to trade a rook very early on and capitalize on position to prevail . . . 

Here, white used the queen to take the rook, putting her out of position, enabling me to focus on trading pieces until enough files opened up so that the rook's abilities could take over the game .  

thanks for the thoughts.  and do you know you to add annotations to the games? 

I don't. I never play here. Just here to read the forums.

        I looked again at your game, and you missed a checkmate on move #32.  You could have moved your queen to E2 and won right there.

       I suppose it is possible for the computer to mess up, but highly unlikely. Again, I am no expert. I'm am average player at best.

        Have fun.

The difference between those two options can be said this way:

If you take the bishop you get a whole piece for nothing. If you take the rook you get a rook for a knight.

Or you can say it this way:

If you take the bishop you are up a whole piece. If you take the rook you are only up the exchange.

***

Some elaboration:

As compensation for the lost exchange white had a better development, but in the continuation he played rather passively I would say which gave black time to activate his pieces. After black's move 16... Bxc3 I think white should play Qxc3 threatening to play Bh6 thus being active. That would probably give excitement for both players.

After 17. bxc3 it was great for black to exchange pieces but not for white. So after black 17... Na5 I think white should avoid the exchange of pieces by moving the bishop back to e2. Instead he played 18. Bd5. After that it was impossible for him to keep the bishop pair.

Black did well in opening up the a-file for the rook and getting a passed pawn.

Anyway, I am no expert either but that is my two cents.

Winning a full piece is better than an exchange so I agree with the computer.

Yes, 3 is better than 2.  Although of course it's not a "blunder"--more inaccurate computer terminology afoot.

Many thanks for your thoughts

I edited my former post and gave some more thoughts.

Blue Nightshade how did you get it 1873 rating as a someone who is an expert that's pretty good

White's Bishop is also well developed, rook not so much, engine might take that into account as well.

Thanks.

Maybe my remark on not being an expert was stupid in that there was no reason to say that. Anyway when is one an expert?

I don't know, but however you got an 1873 on here wihhout playing, kudos. As I recall they started my off at 1000 or so and I dropped to about 700, which I maintain as long as I don't play in bed . . when I am trying to fall aslepp . . 

Without playing??? How did you get that idea? I have played a lot of games here and my rating has had its ups and downs. I just haven't been playing here lately. I will certainly play more games here.

I don't think it is just a blunder because you took the rook instead of the bishop, i believe that knight taking bishop is much better than rook as first off  you keep your knight by taking the bishop, and second of all white's bishop is MUCH stronger than white's rook in this position as it is directed towards black's king, therefore not taking the bishop and taking the rook could lead to a strong attack for white.

Sorry got your comments mixed up with someone else's

So counterintuitive to me, I will remember for next time!