pure function dfnorm(n, a, w)
This function computes the norm of a full N by N matrix,
stored in the array A, that is consistent with the weighted max-norm
on vectors, with weights stored in the array W:
DFNORM = MAX(i=1,...,N) ( W(i) * Sum(j=1,...,N) ABS(a(i,j))/W(j) )
Arguments
| Type |
Intent | Optional | Attributes |
|
Name |
|
|
integer,
|
intent(in) |
|
|
:: |
n |
|
|
real(kind=dp),
|
intent(in) |
|
|
:: |
a(n,n) |
|
|
real(kind=dp),
|
intent(in) |
|
|
:: |
w(n) |
|
Return Value
real(kind=dp)
Variables
| Type |
Visibility | Attributes |
|
Name |
| Initial | |
|
real(kind=dp),
|
public |
|
:: |
an |
|
|
|
|
integer,
|
public |
|
:: |
i |
|
|
|
|
integer,
|
public |
|
:: |
j |
|
|
|
|
real(kind=dp),
|
public |
|
:: |
sum |
|
|
|
Source Code
pure function dfnorm (n, a, w)
integer,intent(in) :: n
real(kind=dp),intent(in) :: a(n,n)
real(kind=dp),intent(in) :: w(n)
real(kind=dp) :: dfnorm
real(kind=dp) an, sum
integer i, j
an = 0.0d0
do i = 1,n
sum = 0.0d0
do j = 1,n
sum = sum + abs(a(i,j))/w(j)
enddo
an = max(an,sum*w(i))
enddo
dfnorm = an
end function dfnorm