*DECK DFMAT SUBROUTINE DFMAT (X, Y, YP) C***BEGIN PROLOGUE DFMAT C***PURPOSE Subsidiary to C***LIBRARY SLATEC C***AUTHOR (UNKNOWN) C***ROUTINES CALLED (NONE) C***COMMON BLOCKS DSAVEX C***REVISION HISTORY (YYMMDD) C ?????? DATE WRITTEN C 891214 Prologue converted to Version 4.0 format. (BAB) C***END PROLOGUE DFMAT DOUBLE PRECISION X,Y,YP,XSAVE,TERM,TANX DIMENSION Y(*),YP(*) COMMON /DSAVEX/ XSAVE, TERM C***FIRST EXECUTABLE STATEMENT DFMAT YP(1) = Y(2) IF (X .EQ. XSAVE) GO TO 10 XSAVE=X TANX= TAN(X/57.2957795130823D0) TERM= 3.0D0/TANX+2.0D0*TANX 10 YP(2) = -TERM*Y(2)-0.7D0*Y(1) RETURN END