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integer function idmax(n, x, incx)
*
* PURPOSE
* finds the index of element having maximum value
* without taking into account the nan(s)...
*
* NOTES
* - original version modified by Bruno (for the nan problem...)
* (01/01/2003)
* - this function return 1 if x has only nan components : may be
* this is not a good behavior
* - this function doesn't test if n<1 or incx<1 : this is done
* by the scilab interface
*
implicit none
integer n, incx
double precision x(incx,*)
double precision xmax
integer i, j
external isanan
integer isanan
idmax = 1
* initialize the max with the first component being not a nan
j = 1
do while ( isanan(x(1,j)) .eq. 1 )
j = j + 1
if ( j .gt. n ) return
enddo
xmax = x(1,j)
idmax = j
* the usual loop
do i = j+1, n
if ( x(1,i) .gt. xmax) then ! a test with a nan must always return false
xmax = x(1,i)
idmax = i
endif
enddo
end
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