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Merge pull request #5649 from hoangviet1985:solve_pow(x,3)=0_opencv300

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This commit is contained in:
Maksim Shabunin 2015-11-22 18:02:40 +00:00
commit ddf293a081
2 changed files with 33 additions and 5 deletions
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27
modules/core/src/mathfuncs.cpp
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@ -44,6 +44,7 @@
#include "precomp.hpp" #include "precomp.hpp"
#include "opencl_kernels_core.hpp" #include "opencl_kernels_core.hpp"
#include <limits> #include <limits>
#include <iostream>
namespace cv namespace cv
{ {
@ -1998,10 +1999,10 @@ int cv::solveCubic( InputArray _coeffs, OutputArray _roots )
double Qcubed = Q * Q * Q; double Qcubed = Q * Q * Q;
double d = Qcubed - R * R; double d = Qcubed - R * R;
if( d >= 0 ) if( d > 0 )
{ {
double theta = acos(R / std::sqrt(Qcubed)); double theta = acos(R / sqrt(Qcubed));
double sqrtQ = std::sqrt(Q); double sqrtQ = sqrt(Q);
double t0 = -2 * sqrtQ; double t0 = -2 * sqrtQ;
double t1 = theta * (1./3); double t1 = theta * (1./3);
double t2 = a1 * (1./3); double t2 = a1 * (1./3);
@ -2010,11 +2011,27 @@ int cv::solveCubic( InputArray _coeffs, OutputArray _roots )
x2 = t0 * cos(t1 + (4.*CV_PI/3)) - t2; x2 = t0 * cos(t1 + (4.*CV_PI/3)) - t2;
n = 3; n = 3;
} }
else if( d == 0 )
{
if(R >= 0)
{
x0 = -2*pow(R, 1./3) - a1/3;
x1 = pow(R, 1./3) - a1/3;
}
else
{
x0 = 2*pow(-R, 1./3) - a1/3;
x1 = -pow(-R, 1./3) - a1/3;
}
x2 = 0;
n = x0 == x1 ? 1 : 2;
x1 = x0 == x1 ? 0 : x1;
}
else else
{ {
double e; double e;
d = std::sqrt(-d); d = sqrt(-d);
e = std::pow(d + fabs(R), 0.333333333333); e = pow(d + fabs(R), 1./3);
if( R > 0 ) if( R > 0 )
e = -e; e = -e;
x0 = (e + Q / e) - a1 * (1./3); x0 = (e + Q / e) - a1 * (1./3);

11
modules/core/test/test_math.cpp
View File

@ -2330,6 +2330,17 @@ void Core_SolvePolyTest::run( int )
pass = pass && div < err_eps; pass = pass && div < err_eps;
} }
//test x^3 = 0
cv::Mat coeffs_5623(4, 1, CV_64FC1);
cv::Mat r_5623(3, 1, CV_64FC2);
coeffs_5623.at<double>(0) = 1;
coeffs_5623.at<double>(1) = 0;
coeffs_5623.at<double>(2) = 0;
coeffs_5623.at<double>(3) = 0;
double prec_5623 = cv::solveCubic(coeffs_5623, r_5623);
pass = pass && r_5623.at<double>(0) == 0 && r_5623.at<double>(1) == 0 && r_5623.at<double>(2) == 0;
pass = pass && prec_5623 == 1;
if (!pass) if (!pass)
{ {
ts->set_failed_test_info(cvtest::TS::FAIL_INVALID_OUTPUT); ts->set_failed_test_info(cvtest::TS::FAIL_INVALID_OUTPUT);