subset(3f) - [M_datapac:VECTOR_OPERATION] extract the elements of a vector
which fall into a user-specified subset (one subset variable)
SUBROUTINE SUBSET(X,N,D,Dmin,Dmax,Newn)
REAL(kind=wp) :: D(:), Dmax ,Dmin, X(:)
INTEGER :: N , Newn
This subroutine retains all observations in the vector X for which
the corresponding elements in the vector D are inside the closed
(inclusive) interval defined by DMIN and DMAX, while deleting all
observations in X corresponding to elements of D outside of this
interval.
Thus all observations in X which correspond to elements in D which
are smaller than DMIN or larger than DMAX are deleted from X.
The use of subset(3f) gives the data analyst the capability
to easily extract subsets of the data prior to data analysis on
each subset.
x the vector of
(unsorted or sorted) observations.
n the integer number of observations
in the vector x.
d the vector
which 'defines' the various
possible subsets of x.
dmin the value
which defines the lower limit
(inclusively) of the particular
subset of interest to be retained.
dmax the value
which defines the upper limit
(inclusively) of the particular
subset of interest to be retained.
newn the integer number of observations
remaining (retained) in x after all
of the observations in x
have been deleted which
correspond to values in the
vector d outside the
interval of interest.
Sample program:
program demo_subset
use M_datapac, only : subset
implicit none
! call subset(x,y)
end program demo_subset
Results:
The original DATAPAC library was written by James Filliben of the Statistical
Engineering Division, National Institute of Standards and Technology.
John Urban, 2022.05.31
CC0-1.0
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| real(kind=wp), | dimension(:) | :: | X | |||
| integer | :: | N | ||||
| real(kind=wp), | dimension(:) | :: | D | |||
| real(kind=wp) | :: | Dmin | ||||
| real(kind=wp) | :: | Dmax | ||||
| integer | :: | Newn |
SUBROUTINE SUBSET(X,N,D,Dmin,Dmax,Newn) REAL(kind=wp) :: D , Dmax , Dmin , hold , pointl , pointu , X INTEGER :: i , k , N , ndel , Newn , newnp1 , nold DIMENSION X(:) DIMENSION D(:) ! ! OUTPUT--THE VECTOR X ! IN WHICH ONLY THOSE VALUES ! HAVE BEEN RETAINED WHICH ! CORRESPOND TO VALUES ! IN THE D VECTOR INSIDE ! (INCLUSIVELY) THE INTERVAL OF ! INTEREST, AND ! THE INTEGER VALUE NEWN ! WHICH GIVES THE NUMBER OF ! OBSERVATIONS RETAINED IN X. ! ALSO, 12 LINES OF SUMMARY INFORMATION ! WILL BE GENERATED INDICATING ! 1) WHAT THE INTERVAL OF INTEREST WAS ! IN THE D VECTOR; ! 2) HOW MANY OBSERVATIONS WERE DELETED; ! 3) WHAT THE OLD (ORIGINAL) SAMPLE SIZE WAS (N); ! 4) WHAT THE NEW SAMPLE SIZE IS (NEWN). ! PRINTING--YES. ! RESTRICTIONS--THERE IS NO RESTRICTION ON THE MAXIMUM VALUE ! OF N FOR THIS SUBROUTINE. ! COMMENT--IN THE END, AFTER THIS SUBROUTINE HAS ! MADE WHATEVER DELETIONS ARE APPROPRIATE, ! THE OUTPUT VECTOR X WILL BE 'PACKED'; ! THAT IS, NO 'HOLES' WILL EXIST IN THE ! VECTOR X--ALL OF THE RETAINED ELEMENTS ! OF X WILL BE PACKED INTO THE FIRST AVAILABLE ! LOCATIONS IN X, WHILE THE REMAINDER ! OF THE N LOCATIONS IN X WILL BE ZERO-FILLED. ! COMMENT--CAUTION IS TO BE EXERCISED IN ! USING THIS SUBROUTINE FOR THE ! FOLLOWING REASON--THE INPUT VECTOR X ! IS IRREVOCABLY ALTERED BY APPLICATION ! OF THIS SUBROUTINE. ALTHOUGH THERE ! MAY BE A CORRESPONDANCE BETWEEN THE ! ELEMENTS OF THE X AND D VECTORS ! BEFORE APPLICATION OF ! THIS SUBROUTINE, THERE WILL ! BE NO CORRESPONDANCE BETWEEN ! X AND D (DUE TO THE PACKING OF ! THE RETAINED ELEMENTS OF X) ! AFTER APPLICATION OF THIS SUBROUTINE. ! TO SUCCESSIVELY EXTRACT EACH POSSIBLE ! SUBSET OF X, IT IS ! RECOMMENDED THAT THE ! ANALYST USE THE SUBSA2 ! SUBROUTINE WHICH LEAVES ! THE ORIGINAL INPUT VECTOR X ! UNALTERED AND OUTPUTS THE ! RETAINED ELEMENTS IN A ! SEPARATE SECOND VECTOR Y. ! COMMENT--IN THE MAIN (CALLING) ROUTINE, IT IS ! PERMISSABLE (IF THE ANALYST SO DESIRES) ! TO USE THE SAME VARIABLE NAME ! IN THE SIXTH ARGUMENT AS USED IN THE SECOND ! ARGUMENT IN THE CALLING SEQUENCE TO THIS ! SUBSET SUBROUTINE--NO CONFLICT WILL RESULT ! IN THE INTERNAL OPERATION OF THE SUBSET ! SUBROUTINE. FOR EXAMPLE, IT IS PERMISSIBLE ! TO HAVE CALL SUBSET(X,N,D,0.5,1.5,N) ! IN WHICH THE VARIABLE NAME N IS USED ! AS BOTH THE SECOND AND SIXTH ARGUMENTS. ! COMMENT--THIS IS ONE OF THE FEW SUBROUTINES IN DATAPAC ! IN WHICH THE INPUT VECTOR X IS ALTERED. ! ORIGINAL VERSION--NOVEMBER 1975. ! UPDATED --FEBRUARY 1976. ! !--------------------------------------------------------------------- ! ! CHECK THE INPUT ARGUMENTS FOR ERRORS ! IF ( N<1 ) THEN WRITE (G_IO,99001) 99001 FORMAT (' ', & &'***** FATAL ERROR--THE SECOND INPUT ARGUMENT TO THE SUBSET SUBROU& &TINE IS NON-POSITIVE *****') WRITE (G_IO,99002) N 99002 FORMAT (' ','***** THE VALUE OF THE ARGUMENT IS ',I0,' *****') RETURN ELSE IF ( N==1 ) THEN WRITE (G_IO,99003) 99003 FORMAT (' ', & &'***** NON-FATAL DIAGNOSTIC--THE SECOND INPUT ARGUMENT TO THE SUBS& &ET SUBROUTINE HAS THE VALUE 1 *****') ELSE hold = X(1) DO i = 2 , N IF ( X(i)/=hold ) GOTO 50 ENDDO WRITE (G_IO,99004) hold 99004 FORMAT (' ', & &'***** NON-FATAL DIAGNOSTIC--THE FIRST INPUT ARGUMENT (A VECTOR) & &TO THE SUBSET SUBROUTINE HAS ALL ELEMENTS =',E15.8,' *****') ENDIF ! !-----START POINT----------------------------------------------------- ! 50 continue pointl = Dmin pointu = Dmax IF ( Dmin>Dmax ) pointl = Dmax IF ( Dmin>Dmax ) pointu = Dmin ! nold = N k = 0 DO i = 1 , nold IF ( D(i)>=pointl .AND. D(i)<=pointu ) THEN k = k + 1 X(k) = X(i) ENDIF ENDDO Newn = k ndel = nold - Newn ! newnp1 = Newn + 1 IF ( newnp1<=nold ) THEN DO i = newnp1 , nold X(i) = 0.0_wp ENDDO ENDIF ! ! WRITE OUT A BRIEF SUMMARY ! WRITE (G_IO,99005) 99005 FORMAT (' ') WRITE (G_IO,99006) 99006 FORMAT (' ','OUTPUT FROM THE SUBSET SUBROUTINE--') WRITE (G_IO,99007) pointl , pointu 99007 FORMAT (' ',7X,'D LIMITS (INCLUSIVE)-- ',E15.8,' AND ', E15.8) WRITE (G_IO,99008) 99008 FORMAT (' ',7X,'ONLY THOSE OBSERVATIONS IN X') WRITE (G_IO,99009) 99009 FORMAT (' ',7X,'WILL BE RETAINED') WRITE (G_IO,99010) 99010 FORMAT (' ',7X,'FOR WHICH THECORRESPONDING ELEMENTS OF D') WRITE (G_IO,99011) 99011 FORMAT (' ',7X,'ARE WITHIN (INCLUSIVE)') WRITE (G_IO,99012) 99012 FORMAT (' ',7X,'THE SPECIFIED LIMITS.') WRITE (G_IO,99013) 99013 FORMAT (' ',7X,'ALL OBSERVATIONS OUTSIDE OF THIS INTERVAL') WRITE (G_IO,99014) 99014 FORMAT (' ',7X,'HAVE BEEN DELETED IN X.') WRITE (G_IO,99015) nold 99015 FORMAT (' ',7X,'THE INPUT NUMBER OF OBSERVATIONS (IN X) IS ', I0) WRITE (G_IO,99016) Newn 99016 FORMAT (' ',7X,'THE OUTPUT NUMBER OF OBSERVATIONS (IN X) IS ', I0) WRITE (G_IO,99017) ndel 99017 FORMAT (' ',7X,'THE NUMBER OF OBSERVATIONS DELETED IS ', I0) ENDIF ! END SUBROUTINE SUBSET