Strange convolution results

[GerritBarrere]

When I try to convolve simple vectors in Prime I get what looks like complex number noise in the result. For example:

This looks like a bug to me. What's up?

[MikeArmstrong]

I can't see the image, can you upload it again or post the worksheet.

Mike

[VladimirN]

Mathcad Prime file can be found in this thread:
http://communities.ptc.com/message/167675

P.S. I have no access to the Prime right now, so I do not see what the problem is.

[VladimirN]

Please delete your duplicate topics:

http://communities.ptc.com/message/167727

http://communities.ptc.com/message/167679

http://communities.ptc.com/message/167678

http://communities.ptc.com/message/167676

[MikeArmstrong]

Why are you cross threading?

Mike

[MikeArmstrong]

Change the formatting from General to Decimal that should sort it.

Mathcad Prime 1.0 has double point floating point precision. It's not possible to represent some numbers, due to rounding errors.

Mike

[VladimirN]

Mike,

You are attached to the message file created for the version of Prime 2.0.

[MikeArmstrong]

Mike,

You are attached to the message file created for the version of Prime 2.0.

Oops, good spot.

Mike

[VladimirN]

You can also compare the results of calculations in Prime 1.0 & 2.0 (where there are no complex values​​):

Prime 1.0:

Prime 2.0 (where there are no complex values):

[MikeArmstrong]

Prime 2.0 (where there are no complex values):

Very strange.

Mike

[RichardJ]

Please do not cross post.

The very small non-zero numbers are just numerical roundoff error.

[VladimirN]

Recently had a discussion about it: http://communities.ptc.com/message/167388#167388

[GerritBarrere]

Thanks for the helpful responses. Sorry about the mutiple posts -- they were being refused all day but were apparently backing up.

I guess the answer is to format results appropriate for the problem. I will experiment with this.