[lmi-commits] [lmi] master 2ad4944 20/23: Record some more observations--no files changed

[Greg Chicares]

branch: master
commit 2ad4944de1b51397eea8d008719acb411e16ec97
Author: Gregory W. Chicares <gchicares@sbcglobal.net>
Commit: Gregory W. Chicares <gchicares@sbcglobal.net>

    Record some more observations--no files changed
    
    Experimentally forced the first N function evaluations (after the first
    two, which evaluate initial bounds) to use binary64 bisection. This only
    harmed performance as measured by the total number of evaluations in the
    system test. Patch follows, with evaluation counts in comments; 7331 is
    the baseline explained in recent commits.
    
    ------------------------ >8 ------------------------
    diff --git a/zero.hpp b/zero.hpp
    index 1b89b0f92..b46233d02 100644
    --- a/zero.hpp
    +++ b/zero.hpp
    @@ -492,7 +492,19 @@ root_type lmi_root
                     ; // Do nothing.
                     }
                 }
    -        if(std::fabs(e) < tol)
    +        // 2: 7331
    +        // 3: 7657
    +        // 4: 7945
    +        // 5: 7781
    +        // 6: 7941
    +        // 7: 7856
    +        if(n_eval < 2)
    +            {
    +            impetus = dithering_near_root;
    +            n = binary64_midpoint(b, c); // "next" iterate
    +            d = e = n - b;
    +            }
    +        else if(std::fabs(e) < tol)
                 {
                 impetus = dithering_near_root;
                 d = e = n - b;
    ------------------------ >8 ------------------------
    [This empty commit message ends here.]