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/* Copyright (c) 2008-2022 the MRtrix3 contributors.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Covered Software is provided under this License on an "as is"
* basis, without warranty of any kind, either expressed, implied, or
* statutory, including, without limitation, warranties that the
* Covered Software is free of defects, merchantable, fit for a
* particular purpose or non-infringing.
* See the Mozilla Public License v. 2.0 for more details.
*
* For more details, see http://www.mrtrix.org/.
*/
#ifndef __math_chebyshev_h__
#define __math_chebyshev_h__
#include "math/math.h"
namespace MR
{
namespace Math
{
namespace Chebyshev
{
template <typename T> inline T eval (const double* coef, const int order, const T lower, const T upper, const T x)
{
T y = (2.0*x - lower - upper) / (upper - lower);
T d = 0.0, dd = 0.0;
for (int i = order; i >= 1; i--) {
T temp = d;
d = 2.0*y*d - dd + coef[i];
dd = temp;
}
return (y*d - dd + 0.5 * coef[0]);
}
}
}
}
#endif
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