81 void run( Real &alpha, Real &fval,
int &ls_neval,
int &ls_ngrad,
84 Real tol = std::sqrt(ROL_EPSILON<Real>()),
zero(0), one(1), two(2), five(5);
91 Real c = two/(one+sqrt(five));
105 if ( val_tr < val_tl ) {
106 if (
LineSearch<Real>::status(
LINESEARCH_GOLDENSECTION,ls_neval,ls_ngrad,tr,fval,gs,val_tr,x,s,obj,con) ) {
116 if ( val_tl < val_tr ) {
126 Real tc1 = c*tl + (one-c)*tr;
133 Real tc2 = (one-c)*tl + c*tr;
140 if ( val_tl <= val_tc1 && val_tl <= val_tc2 && val_tl <= val_tr ) {
144 else if ( val_tc1 <= val_tl && val_tc1 <= val_tc2 && val_tc1 <= val_tr ) {
148 else if ( val_tc2 <= val_tl && val_tc2 <= val_tc1 && val_tc2 <= val_tr ) {
157 while ( !
LineSearch<Real>::status(
LINESEARCH_GOLDENSECTION,ls_neval,ls_ngrad,t,fval,gs,val_t,x,s,obj,con)
158 && (std::abs(tl-tr) >=
tol_) ) {
159 if ( val_tc1 > val_tc2 ) {
165 tc2 = (one-c)*tl + c*tr;
177 tc1 = c*tl + (one-c)*tr;
184 if ( val_tl <= val_tc1 && val_tl <= val_tc2 && val_tl <= val_tr ) {
188 else if ( val_tc1 <= val_tl && val_tc1 <= val_tc2 && val_tc1 <= val_tr ) {
192 else if ( val_tc2 <= val_tl && val_tc2 <= val_tc1 && val_tc2 <= val_tr ) {
204 if ( alpha < ROL_EPSILON<Real>() ) {
205 btls_->run(alpha,fval,ls_neval,ls_ngrad,gs,s,x,obj,con);