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```SUBROUTINE ATSM

PURPOSE
NDIM POINTS OF A GIVEN TABLE WITH MONOTONIC ARGUMENTS ARE
SELECTED AND ORDERED SUCH THAT
ABS(ARG(I)-X).GE.ABS(ARG(J)-X) IF I.GT.J.

USAGE
CALL ATSM (X,Z,F,IROW,ICOL,ARG,VAL,NDIM)

DESCRIPTION OF PARAMETERS
X	  - THE SEARCH ARGUMENT.
Z	  - THE VECTOR OF ARGUMENT VALUES (DIMENSION IROW).
THE ARGUMENT VALUES MUST BE STORED IN INCREASING
OR DECREASING SEQUENCE.
F	  - IN CASE ICOL=1, F IS THE VECTOR OF FUNCTION VALUES
(DIMENSION IROW).
IN CASE ICOL=2, F IS AN IROW BY 2 MATRIX. THE FIRST
COLUMN SPECIFIES THE VECTOR OF FUNCTION VALUES AND
THE SECOND THE VECTOR OF DERIVATIVES.
IROW   - THE DIMENSION OF VECTOR Z AND OF EACH COLUMN
IN MATRIX F.
ICOL   - THE NUMBER OF COLUMNS IN F (I.E. 1 OR 2).
ARG	  - THE RESULTING VECTOR OF SELECTED AND ORDERED
ARGUMENT VALUES (DIMENSION NDIM).
VAL	  - THE RESULTING VECTOR OF SELECTED FUNCTION VALUES
(DIMENSION NDIM) IN CASE ICOL=1. IN CASE ICOL=2,
VAL IS THE VECTOR OF FUNCTION AND DERIVATIVE VALUES
(DIMENSION 2*NDIM) WHICH ARE STORED IN PAIRS (I.E.
EACH FUNCTION VALUE IS FOLLOWED BY ITS DERIVATIVE
VALUE).
NDIM   - THE NUMBER OF POINTS WHICH MUST BE SELECTED OUT OF
THE GIVEN TABLE (Z,F).

REMARKS
NO ACTION IN CASE IROW LESS THAN 1.
IF INPUT VALUE NDIM IS GREATER THAN IROW, THE PROGRAM
SELECTS ONLY A MAXIMUM TABLE OF IROW POINTS.  THEREFORE THE
USER OUGHT TO CHECK CORRESPONDENCE BETWEEN TABLE (ARG,VAL)
AND ITS DIMENSION BY COMPARISON OF NDIM AND IROW, IN ORDER
TO GET CORRECT RESULTS IN FURTHER WORK WITH TABLE (ARG,VAL).
THIS TEST MAY BE DONE BEFORE OR AFTER CALLING
SUBROUTINE ATSM.
SUBROUTINE ATSM ESPECIALLY CAN BE USED FOR GENERATING THE
TABLE (ARG,VAL) NEEDED IN SUBROUTINES ALI, AHI, AND ACFI.

SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED
NONE

METHOD
SELECTION IS DONE BY SEARCHING THE SUBSCRIPT J OF THAT
ARGUMENT, WHICH IS NEXT TO X (BINARY SEARCH).
AFTERWARDS NEIGHBOURING ARGUMENT VALUES ARE TESTED AND
SELECTED IN THE ABOVE SENSE.

```