Hi Martin, Davide

I am still working about Vectors and what make me wonder is why using symbolic optimization I do not have a correct result for what concern the dot product (Scalar product) of 2 vectors .



There is something that for sure I am missing ..or I am asking too much to Smath ( I was starting to try the same in WxMaxima , if it works with this tool probably using the Maxima plug-in it should work from within Smath too)

Best regards

Franco

Edited by moderator 05 October 2016 00:42:46(UTC)  | Reason: discussion moved from this point on

I also think that it is a bug, has been introduced after 97.5737

Sorry Jean but I am not able to understand your answer even reading the .sm file you attached.
I am not using/defining any function in my example I am just multiplying in a scalar way same vectors ..or at least I guess so.


Best regards

Franco

Jean,

I am able to open your example but I simply do not understand the relationship of you example with the issue I am reporting.
As already stated I don't want with my calculations to come up with a number but I would like to see in Smath that the scalar product ( or dot product ) of 2 vectors is the sum of the products of the components on each axis i.e that what should comes up from the symbolic calculations of the product is what is highlighted in yellow herewith :



I don't know if this request is too much for the internal Symbolic engine.

Moreover despite what is shown in the Davide's e-mail I can't evaluate numerically the expression of vector A but I have the expression in red with the error message A.x is not defined ( even because it would be impossible to evaluate it numerically ..I guess or I don't understand clearly the meaning of the "=" operator ).

I am using Smath Studio 0.98 build 6103.

I am pushed to think that Smath does not recognize that the expression of A is the definition of a vector as well the definition of B; so that when I apply the dot vector operator on these structure doesn't happen anything and are not applied the correct simplification rules ( but this is just my modest opinion about what is happening ).

Best regards

Franco

Franco,

No matter what A,B,C will be, from the onset your attempt is wrong.
Why wrong ? You have valued e(x,y,z). So, the next WHATEVER can't
be [A,B,C]*e(x,y,z) but e(x,y,z)*[A,B,C]. That's what the work sheet
previousely attached demonstrates for the 1D, 2D, 3D applications.

I don't understand "projection on axes...". There are 24 ways of
representing a 3D axis sytem. Mathematica and Mathcad don't have
identical system. Smath has no 3D system except the one from
"CreateMesh" or its native 3D plot. The 3 orthogonal directions
result from "monkey business creation".

Jean

Hi Andrey

Thanks a lot for the new RC5 it improves on the previous one but I guess that there are still some refinements to accomplish ...if possible.
See herewith , hoping that I was able to explain correctly the issue .

Thanks again and best regards

Franco

I think this is not safe until you assume that every unknown is always a scalar (that might cause several troubles) or there is some way to declare the type of an unknown (scalar/matrix/vector).

About the previous post, by default SMath tries to returns the most compact result; I guess might be matter for the expand() function.

Edited by user 11 October 2016 10:54:45(UTC)  | Reason: Not specified

Just for information. I am not sure whether this is helpful.

Edited by user 11 October 2016 16:44:26(UTC)  | Reason: Not specified

Why should there be more arguments ?