CKR2CH    CKR2CH    CKR2CH    CKR2CH    CKR2CH    CKR2CH    CKR2CH    
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                              ******

SUBROUTINE CKR2CH (RNUM, STR, I, KERR)
Returns a character string representation of a real number
and the effective length of the string.

INPUT
RNUM      - Real scalar, to be converted to a string;
            the maximum magnitude of RNUM is machine-dependent.

OUTPUT
STR      - Character string, left-justified representation of RNUM;
           that is, RNUM=  0.0      returns STR=" 0.00"
                 RNUM= -10.5     returns STR="-1.05E+01"
                 RNUM= 1.86E-100 returns in STR=" 1.86E-100"
                 the minimum length of STR required is 5
I        - Integer scalar, total non-blank characters in RNUM.
KERR     - Logical, character length error flag.