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Merge pull request #5651 from hoangviet1985:fix_solvePoly_3.0.0

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Vadim Pisarevsky
2015-12-07 10:12:54 +00:00
parent d4245aa45c b96def885f
commit d19897b734
2 changed files with 91 additions and 1 deletions
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43
modules/core/src/mathfuncs.cpp
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@@ -2108,12 +2108,53 @@ double cv::solvePoly( InputArray _coeffs0, OutputArray _roots0, int maxIters )
{
p = roots[i];
C num = coeffs[n], denom = coeffs[n];
int num_same_root = 1;
for( j = 0; j < n; j++ )
{
num = num*p + coeffs[n-j-1];
if( j != i ) denom = denom * (p - roots[j]);
if( j != i )
{
if ( (p - roots[j]).re != 0 || (p - roots[j]).im != 0 )
denom = denom * (p - roots[j]);
else
num_same_root++;
}
}
num /= denom;
if( num_same_root > 1)
{
double old_num_re = num.re;
double old_num_im = num.im;
int square_root_times = num_same_root % 2 == 0 ? num_same_root / 2 : num_same_root / 2 - 1;
for( j = 0; j < square_root_times; j++)
{
num.re = old_num_re*old_num_re + old_num_im*old_num_im;
num.re = sqrt(num.re);
num.re += old_num_re;
num.im = num.re - old_num_re;
num.re /= 2;
num.re = sqrt(num.re);
num.im /= 2;
num.im = sqrt(num.im);
if( old_num_re < 0 ) num.im = -num.im;
}
if( num_same_root % 2 != 0){
Mat cube_coefs(4, 1, CV_64FC1);
Mat cube_roots(3, 1, CV_64FC2);
cube_coefs.at<double>(3) = -(pow(old_num_re, 3));
cube_coefs.at<double>(2) = -(15*pow(old_num_re, 2) + 27*pow(old_num_im, 2));
cube_coefs.at<double>(1) = -48*old_num_re;
cube_coefs.at<double>(0) = 64;
solveCubic(cube_coefs, cube_roots);
if(cube_roots.at<double>(0) >= 0) num.re = pow(cube_roots.at<double>(0), 1./3);
else num.re = -pow(-cube_roots.at<double>(0), 1./3);
num.im = sqrt(pow(num.re, 2) / 3 - old_num_re / (3*num.re));
}
}
roots[i] = p - num;
maxDiff = std::max(maxDiff, cv::abs(num));
}