Global Stiffness Matrix

nibas · Post by **nibas** » Wed Dec 13, 2006 6:58 am

Where is the Global stiffness matrix of the structure after the rigidDiaphragm constrain has been imposed???

I have only find the element's Stiffness Matrix.

Is there a function that returns the Global stiffness matrix?

Post by **fmk** » Wed Dec 13, 2006 1:15 pm

no function exists to return the matrix. it is stored in the system of equation in whatever internal format the system of equation object uses.

nibas · Post by **nibas** » Thu Dec 14, 2006 8:15 am

Thank you fmk,

I 'll see that

nibas · Post by **nibas** » Fri Dec 15, 2006 9:23 am

Frank, I found theSysOfEqn, and inside it has cector X.

Is X the Stiffness Matrix?

If it is, why it is a Vector and not a Matrix,

and in which way is the data stored there?

I sent you an e-mail with a print/screen of the current code's view.

Is there any documentation that explains the theory of the code

and how it is developed in the programm???

Because the API allthought is very good,

it isn't complete enough for someone to understand.

Thanks a very lot

Post by **fmk** » Fri Dec 15, 2006 10:14 am

no A is the stiffness matrix, the SOE stores Ax=b (which is why x is a Vector) .. and if you are going to try to print out the A matrix I suggest you use a different SOE than the Sparse one, the BandedGeneral or FullGeneral ones .. you may need to look at Lapack documentation to see how the A is stored as it is not stored in a Matrix object but rather the data is stored in an array of double .. as for documentation you can have a look at my dissertation, which can be found here
http://ce.berkeley.edu/~fmckenna/dissertation.html

which has a link to a .ps file