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Emerald II

## Rank matrix with mixed units

Is it an error in Prime or I do somethink wrong? The Prime 2 sheet in attch.

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## Re: Rank matrix with mixed units

Solution:

But I think not all is correct in Prime! Jakov Kucan, where are yuo!?

17 REPLIES 17

## Re: Rank matrix with mixed units

I think it is an error. Or?

## Re: Rank matrix with mixed units

I don't think it's an error. To find the rank of a matrix one has to perform some operations that involve subtraction of terms from different rows. This only makes sense if all the terms in the matrix are of the same type. The determinant works for your examp;les because items of different type are only multiplied together (which can make sense).

Alan

## Re: Rank matrix with mixed units

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.

## Re: Rank matrix with mixed units

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. )

## Re: Rank matrix with mixed units

Thanks, Werner.

(I will try to create one correct system for this circuit with rank(M)=rank(M1)=number of unknowns)

## Re: Rank matrix with mixed units

 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:

## Re: Rank matrix with mixed units

Solution:

But I think not all is correct in Prime! Jakov Kucan, where are yuo!?

## Re: Rank matrix with mixed units

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.