Single element matrix?

[RadovanOmorjan]

I hope this is not posted before (I doubt). Is this correct? I think a*b should be matrix not scalar. This is also in Mathcad 14.

Regards,
Radovan

[RichardJ]

It's the product of two single element vectors, and the behavior is exactly the same as if they were two two element vectors. Which is what I would expect.

Richard

[RadovanOmorjan]

On 8/24/2009 8:30:15 AM, rijackson wrote:
>It's the product of two single
>element vectors, and the
>behavior is exactly the same
>as if they were two two
>element vectors. Which is what
>I would expect.
>
>Richard

Yes, you are right. Product means here - "scalar product of two vectors" - the result is scalar.

Scalars, Vectors, Matrices and product operator - three different things.

I forgot that, sorry 😞

Radovan

[TomGutman]

A long standing issue, and a result that is different in different versions of Mathcad.

The problem is lack of a proper distinction between vectors and matrices. A one element array can be equally viewed as a one element vector or as a one by one matrix. If it is viewed as a one element vector, then the product is the vector dot product and properly a scalar. If it is viewed as a one by one matrix then the product should be a matrix product, another one by one matrix. I have sheets that work with variable sized matrices (depending on the data) and need to have the limiting case of a one by one matrix handled as a special case because of this odd behaviour.
__________________
� � � � Tom Gutman

[RadovanOmorjan]

On 8/24/2009 3:28:20 PM, Tom_Gutman wrote:
>A long standing issue, and a
>result that is different in
>different versions of Mathcad.
You are quite right. For instance, in one Mathcad version you can not define a variable as 1x1 matrix/vector, but the result of calculation could be a 1x1 matrix/vector - what to say? On another version of Mathcad - different behaviour. Quite confusing.

Radovan

[JCBanks]

I have used a 1x1 multiplied by a 1x1 as
a practical problem using Fortran. Therefore,
I recommend that PTC considers this Fix.

Julio C. Banks, MSME, P.E.