Unverified Commit c89add10 authored by Oleg Alexandrov's avatar Oleg Alexandrov Committed by GitHub
Browse files

Brent root fix (#362) 

* Bugfix for brent_root: It could fail to identify the bracket correctly

* Refine the bugfix per Wikipedia, and fix the test
parent 5ef20008

src/Utilities.cpp

+6 −0
Original line number Diff line number Diff line
@@ -296,6 +296,12 @@ double brentRoot(double lowerBound, double upperBound, 
    previousPoint = currentPoint;

    previousFunc = currentFunc;

    nextFunc = func(nextPoint);



    // This is a bugfix. Without it, the code gets lost and can't find the solution.

    // See also the implementation at https://en.wikipedia.org/wiki/Brent%27s_method

    if (nextFunc == 0)

      return nextPoint;



    if (counterFunc * nextFunc < 0) {

      currentPoint = nextPoint;

      currentFunc = nextFunc;

tests/SarTests.cpp

+2 −2
Original line number Diff line number Diff line
@@ -84,10 +84,10 @@ TEST_F(SarSensorModel, computeGroundPartials) { 
  ASSERT_EQ(partials.size(), 6);

  EXPECT_NEAR(partials[0], 6.5128150576280552e-09, 1e-8);

  EXPECT_NEAR(partials[1], -5.1810407815840636e-15, 1e-8);

  EXPECT_NEAR(partials[2], -0.13309947654685725, 1e-8);

  EXPECT_NEAR(partials[2], -0.13333333443071135, 1e-8);

  EXPECT_NEAR(partials[3], -33.057625791698072, 1e-8);

  EXPECT_NEAR(partials[4], 6.1985123841926308e-05, 1e-8);

  EXPECT_NEAR(partials[5], 0.007743051337209989, 1e-8);

  EXPECT_NEAR(partials[5], 0.0077565105243007169, 1e-8);

}



TEST_F(SarSensorModel, imageToProximateImagingLocus) {