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Full Version: HP Prime Matrix TERRIBLE bug and question
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Hi everyone, i found this terrible bug using the Home mode, and the CAS mode. I'm not sure if this was already reported, because is really anoying.

CAS mode:

Home mode: BUG

BY THE WAY. Does anyone know if its possible to do operations with matrices and/or polynomials using modulo 2 arithmetic?
Thanks.

Edited: 24 Nov 2013, 11:58 p.m.

Wow, that is a bad bug.

For modulo 2 arithmetic, just use the MOD command. Need to be in CAS view, though. I think Home view expects real-valued arguments (i.e. numbers and not matrices).

Thanks Han, I used MOD on CAS Mode and it worked fine (using capital letters).

That bug only happens when the matrices are big, I don't know why. I hope they fixt it with an update :)

I think the vector notation for [1 1 0 1 1 0 1] screws up the calculator in HOME. Please use the matrix notation instead, i.e. [[1 1 0 1 1 0 1]], and it works fine. The product of the two matrices also carries the matrix notation.

Edited: 25 Nov 2013, 12:41 a.m.

Matrices are just groupings of elements that can be numbers or symbols. Matrix arithmetic is in fact by default numeric, although symbolic operations are fine in CAS. The example shown above should work perfectly in Home view.

Good point. You are actually multiplying a 1x7 matrix by a 7x3 matrix to obtain a 1x3 matrix as the result, i.e. [[4 3 2]]. The easiest way to create matrices is to use textbook entry, which will automate the process and avoid syntax errors.

Quote:
I think the vector notation for [1 1 0 1 1 0 1] screws up the calculator in HOME. Please use the matrix notation instead, i.e. [[1 1 0 1 1 0 1]], and it works fine. The product of the two matrices also carries the matrix notation.

Ohh now I see. I was using Shift + 5 to create the matrix, but I didn't realize that the square bracket is different.

No, the square bracket is the same; it's just that you need two of them. The outer set of brackets denote the overall matrix, and the inner ones denote the rows. So, The 3x7 matrix is [[1,0,0],[0,1,0],....[1,1,0]].

It is still a bug. Anything that screws up is a bug. Either make the operation illegal with an error message or make it work. It shouldn't return bogus results.

Pauli

Yes, but this is a quick workaround. The HP engineers need some time to fix it. :)

Well, if you try certain matrix operations such as transpose on a vector it will definitely give an error message. But, I agree that the operation shown in the OP should also fail rather than give a bogus result. By the same token, you can't perform vector operations such as dot product on matrices.

Edited: 25 Nov 2013, 1:22 a.m.

Press Shift-5 twice to get the matrix notation, i.e. double square brackets.

Edited: 25 Nov 2013, 1:24 a.m.

FYI, the TRN function works fine for a vector but the result is a matrix!

There's something as bad as bugs - inconsistency in the implementation. That leads to never knowing how to correctly do things, and always doubting (ie. not trusting) the results!

Ain't that true!

Quote:
There's something as bad as bugs - inconsistency in the implementation. That leads to never knowing how to correctly do things, and always doubting (ie. not trusting) the results!

Well said! This is exactly why I've avoiding buying a Prime. Beta testing should have caught virtually all the bugs on all the recently released HP calculators, but there's this push to get stuff out the door when it's far from ready. This might be fine and necessary (from a marketing perspective) for certain devices but not for something who's purpose is to be trusted.

Thanks Katie! I couldn't have said it better.

d:-I

I saw these bugs with matrices.
I'm looking at the 39gII firmware update to see if the bugs are still here.

This also is my motive to not yet buy the Prime. I remember the Prime has been announced quite some time ago. So I thought all the pre-release users of devoted calculator lovers would have traced all the flaws and errors and bugs the device could have. And the answer is: no, there still will be a lot of bugs the weeks and months to come. So I still will wait before I buy this prematurely highly praised super calculator.

Don't buy it. It will drive you crazy. See my new post above.