SUBROUTINE RHOA(A,LAMBDA,X,PAR,IPAR) DOUBLE PRECISION A(1),LAMBDA,X(1),PAR(1) INTEGER IPAR(1) C C PAR(1:*) AND IPAR(1:*) ARE ARRAYS FOR (OPTIONAL) USER PARAMETERS, C WHICH ARE SIMPLY PASSED THROUGH TO THE USER WRITTEN SUBROUTINES C RHOA, RHOJS. C C CALCULATE AND RETURN IN A THE VECTOR Z SUCH THAT C RHO(Z,LAMBDA,X) = 0 . C RETURN END .