The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> Circuit Simulators >> Sparse matrix
https://designers-guide.org/forum/YaBB.pl?num=1049500807

Message started by vova on Apr 4^th, 2003, 4:00pm

Title: Sparse matrix
Post by vova on Apr 4^th, 2003, 4:00pm

I am using Sparse V1.3a and need to get a pointer to an existing element knowing only row and column numbers. Actually Sparse which I am using does not have a function for that. So I just want to know if
such a function already exist, or I am forced to write my own, modifing spPrint()?

Thanks,
Vova.

Title: Re: Sparse matrix
Post by Ken Kundert on Apr 4^th, 2003, 4:17pm

The function spGetElement allows you to get a pointer to an existing element knowing only the row and column number. It will, however, create the element if it does not already exist.

-Ken

Title: Re: Sparse matrix
Post by vova on Apr 4^th, 2003, 5:06pm

I don't want to waste memory. I have a look at spGetElement. It seems I can use spcFindElementinCol() with NO as a last argumen. But I am cunfused, will it work for col=row?

Thanks a lot,
Vova.

Title: Re: Sparse matrix
Post by Ken Kundert on Apr 8^th, 2003, 3:24pm

There is a function in the Spice3 compatibility code in spSMP.c that does what you want. It is SMPfindElt(). Do you have that code?

-Ken

Title: Re: Sparse matrix
Post by vova on Apr 10^th, 2003, 1:55pm

Yes, I have spsmp.c. Thanks for letting me know about SMPfindElt(), now I am using this function.

Vova.

Title: Re: Sparse matrix
Post by rf-design on Oct 13^th, 2003, 2:06am

I am interessted in circuit simulation implementation.

Does anybody now about

1. Solving sparse matrix by combinations of direct and iterative method. Where pivot ordering and selection generate side information which part to solve direct and which iterative.

2. Is there a reuse of pivot information while processing different transient steps?

3. Does the pivot selection and reordering change much at circuit discontiniousities?

4. Does circuit simulator implementations exist based on state variable approach. How these implement rank deficiencies?