39 lines
935 B
Fortran
39 lines
935 B
Fortran
integer function idamaxf(n,dx,incx)
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c
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c finds the index of element having max. absolute value.
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c jack dongarra, linpack, 3/11/78.
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c modified 3/93 to return if incx .le. 0.
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c modified 12/3/93, array(1) declarations changed to array(*)
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c
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double precision dx(*),dmax
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integer i,incx,ix,n
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c
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idamaxf = 0
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if( n.lt.1 .or. incx.le.0 ) return
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idamaxf = 1
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if(n.eq.1)return
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if(incx.eq.1)go to 20
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c
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c code for increment not equal to 1
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c
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ix = 1
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dmax = dabs(dx(1))
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ix = ix + incx
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do 10 i = 2,n
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if(dabs(dx(ix)).le.dmax) go to 5
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idamaxf = i
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dmax = dabs(dx(ix))
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5 ix = ix + incx
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10 continue
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return
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c
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c code for increment equal to 1
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c
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20 dmax = dabs(dx(1))
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do 30 i = 2,n
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if(dabs(dx(i)).le.dmax) go to 30
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idamaxf = i
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dmax = dabs(dx(i))
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30 continue
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return
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end
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