?
Solved

Matrix discretisation routine in C

Posted on 2001-07-09
4
Medium Priority
?
271 Views
Last Modified: 2006-11-17
Looking for the EFFICIENT algorithm implimented in C.
0
Comment
Question by:john_t
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
4 Comments
 
LVL 4

Expert Comment

by:prashant_n_mhatre
ID: 6269104
state-space matrices?
0
 

Author Comment

by:john_t
ID: 6270133
yes
0
 
LVL 4

Expert Comment

by:prashant_n_mhatre
ID: 6270164
If you have access to MATLAB, have a look at MATLAB c2d command. They use matrix discretization using matrix exponentials but for you it will be very difficult to implement.

I know 3 routines do this. The good one is in Fortran (not in C) and it is easy to understand. I'll get it tomorrow.
0
 
LVL 4

Accepted Solution

by:
prashant_n_mhatre earned 800 total points
ID: 6272990
Here it goes...
If you don't understand terminology...let me know..


c     returns the discretized state and input transition matrices

     subroutine discret(a,b,delt,phi,gam,nord,ni)
     implicit real*8(a-h,o-z)

     dimension si(100,100),q(100,100),sb(100,100),prod(100,100)
     dimension a(100,100),b(100,15)
     dimension phi(100,100),gam(100,15)

     do i=1,nord
        q(i,i)=1.0
        si(i,i)=q(i,i)
      end do

     do k=150,1,-1
        if(k.eq.1) then
           call matmul(si,b,nord,nord,ni,sb,100,100,100)
           do i=1,nord
              do j=1,ni
                     gam(i,j)=sb(i,j)*delt
               end do
            end do
           call matmul(a,si,nord,nord,nord,prod,100,100,100)
           do i=1,nord+1
              do j=1,nord+1
                     phi(i,j)=prod(i,j)*delt+q(i,j)
               end do
            end do
        else
           call matmul(a,si,nord+1,nord+1,nord+1,prod,100,100,100)
           do i=1,nord+1
              do j=1,nord+1
                     si(i,j)=q(i,j)+prod(i,j)*delt/float(k)
               end do
            end do
        endif
      end do

     return
     end

c     _______________________________________________________________________________
c     subroutine to obtain the product of two matrices
     
     subroutine matmul(a2,b2,m3,n3,iq,c1,ia,ib,ic)
     implicit real*8(a-h,o-z)

     dimension a2(ia,1),b2(ib,1),c1(ic,1)

     do i=1,m3
        do j=1,iq
           c1(i,j)=0.0
           do k=1,n3
                  c1(i,j)=c1(i,j)+a2(i,k)*b2(k,j)
            end do
         end do
      end do

     return
     end
c     _______________________________________________________________________________

0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Computer science students often experience many of the same frustrations when going through their engineering courses. This article presents seven tips I found useful when completing a bachelors and masters degree in computing which I believe may he…
This article will show how Aten was able to supply easy management and control for Artear's video walls and wide range display configurations of their newsroom.
In this seventh video of the Xpdf series, we discuss and demonstrate the PDFfonts utility, which lists all the fonts used in a PDF file. It does this via a command line interface, making it suitable for use in programs, scripts, batch files — any pl…
Six Sigma Control Plans

765 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question