ACCEPTED SOLUTION
Accepted Solutions
Solution:
But I think not all is correct in Prime! Jakov Kucan, where are yuo!?
Fully agreed. I, too, won't consider this an error.
This only makes sense if all the terms in the matrix are of the same type.
And thats the reason the numeric processor fails - its aware of units. While I don't consider it a bug or error I can see that it could be convenient if Prime would see the unit not as a real unit but rather as a simple factor in that case.
The symbolic processor is not aware of units and treats it as normal (unknown) variables. Consequently a symbolic evaluation works.
I think must be so (the system has infinity numbers of solutions) - Prime must have a new rank function.
(I think I am a first man of the World who try to calculate a rank of one mixed units matrix. 
)
Your routine can be written more compact using vectorization, but it (and yours) yields wrong results in some (not so rare) occasions:
Werner Exinger wrote:
Your routine can be written more compact using vectorization, but it (and yours) yields wrong results in some (not so rare) occasions:
Yes! My routine is better for education
And as in "old dood" Mathcad 15:
m := 1 km := 1000m V :=1 etc
Yes! My routine is better for education
Matter of taste and in this case I tend to disagree.
But the critical point is that the routine (both) aren't correct. They yield wrong results as in my second example. They shouldn't give a correct result ("if m=Ohm then rank is 1, otherwise its 2") or at least fail in the secon example if the units don't "match". Writing the routine that way would require loops instead of vectorization anyway 😉
Units still are not fully supported throughout - see changing display units for single elelements of a matrix or, as here some functions like rank.
In urgent need you may use the attached, which, when numerically evaluated gives the appropriate error message if the units don't fit and which can be used to get the correct result with symbolical eval. Unfortunately we can't put the latter in a single function as the intermediate numeric evaluation (matrix M2) is needed to get the units correctly simplified an cannot be achieved inside a program, AFAIK.
Thanks, Werner.
(I will try to create one correct system for this circuit with rank(M)=rank(M1)=number of unknowns)
Valery Ochkov wrote:
I will try to create one correct system for this circuit with rank(M)=rank(M1)=number of unknowns)
I think must be so:
As the symbolics is not aware of units its right.
But using a modifier like "fully" I would have expected muPad to give me a more complete result by telling me, that the rank = 2 only if V is not Omega*A and its 1 otherwise.
