*IF DEF,C91_2A                                                             SQRTHF2A.2      
C ******************************COPYRIGHT******************************    GTS2F400.9451   
C (c) CROWN COPYRIGHT 1995, METEOROLOGICAL OFFICE, All Rights Reserved.    GTS2F400.9452   
C                                                                          GTS2F400.9453   
C Use, duplication or disclosure of this code is subject to the            GTS2F400.9454   
C restrictions as set forth in the contract.                               GTS2F400.9455   
C                                                                          GTS2F400.9456   
C                Meteorological Office                                     GTS2F400.9457   
C                London Road                                               GTS2F400.9458   
C                BRACKNELL                                                 GTS2F400.9459   
C                Berkshire UK                                              GTS2F400.9460   
C                RG12 2SZ                                                  GTS2F400.9461   
C                                                                          GTS2F400.9462   
C If no contract has been raised with this copy of the code, the use,      GTS2F400.9463   
C duplication or disclosure of it is strictly prohibited.  Permission      GTS2F400.9464   
C to do so must first be obtained in writing from the Head of Numerical    GTS2F400.9465   
C Modelling at the above address.                                          GTS2F400.9466   
C ******************************COPYRIGHT******************************    GTS2F400.9467   
C                                                                          GTS2F400.9468   
CLL Function SQRTHF                                                        SQRTHF2A.3      
CLL                                                                        SQRTHF2A.4      
CLL Purpose: Portable verion of Cray library function to compute           TS220993.90     
CLL          square root of ARG1                                           TS220993.91     
CLL                                                                        TS220993.92     
CLL Tested under compiler:   fort77                                        TS220993.93     
CLL Tested under OS version: HP-UX A.08.07                                 TS220993.94     
CLL                                                                        SQRTHF2A.6      
CLL  Model            Modification history:                                SQRTHF2A.7      
CLL version  Date                                                          SQRTHF2A.8      
CLL  3.2   16/07/93   New deck. Tracey Smith.                              SQRTHF2A.9      
CLL  3.3   22/09/93   Improved comments  Tracey Smith                      TS220993.95     
CLL                                                                        TS220993.96     
CLL Programming Standard: UM Doc Paper 3, version 5 (08/12/92)             TS220993.97     
CLL                                                                        SQRTHF2A.10     

      REAL FUNCTION SQRTHF(ARG1)                                           ,1SQRTHF2A.11     
      IMPLICIT NONE                                                        SQRTHF2A.12     
      REAL ARG1                                                            SQRTHF2A.13     
      IF(ARG1.LT.0) THEN                                                   SQRTHF2A.14     
        WRITE(6,*) 'Error: Attempt to SQRT a negative value'               SQRTHF2A.15     
        CALL ABORT                                                         SQRTHF2A.16     
      ELSE                                                                 SQRTHF2A.17     
        SQRTHF=SQRT(ARG1)                                                  SQRTHF2A.18     
      END IF                                                               SQRTHF2A.19     
      END                                                                  SQRTHF2A.20     
*ENDIF                                                                     SQRTHF2A.21