File: fnorm.f

package info (click to toggle)
scilab 4.0-12
  • links: PTS
  • area: non-free
  • in suites: etch, etch-m68k
  • size: 100,640 kB
  • ctags: 57,333
  • sloc: ansic: 377,889; fortran: 242,862; xml: 179,819; tcl: 42,062; sh: 10,593; ml: 9,441; makefile: 4,377; cpp: 1,354; java: 621; csh: 260; yacc: 247; perl: 130; lex: 126; asm: 72; lisp: 30
file content (25 lines) | stat: -rw-r--r-- 874 bytes parent folder | download | duplicates (14) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
 
C/MEMBR ADD NAME=FNORM,SSI=0
      double precision function fnorm (n, a, w)
clll. optimize
c-----------------------------------------------------------------------
c%purpose
c this function computes the norm of a full n by n matrix,
c stored in the array a, that is consistent with the weighted max-norm
c on vectors, with weights stored in the array w..
c   fnorm = max(i=1,...,n) ( w(i) * sum(j=1,...,n) abs(a(i,j))/w(j) )
c!
c-----------------------------------------------------------------------
      integer n,   i, j
      double precision a,   w, an, sum
      dimension a(n,n), w(n)
      an = 0.0d+0
      do 20 i = 1,n
        sum = 0.0d+0
        do 10 j = 1,n
 10       sum = sum + abs(a(i,j))/w(j)
        an = max(an,sum*w(i))
 20     continue
      fnorm = an
      return
c----------------------- end of function fnorm -------------------------
      end