53 lines
1.5 KiB
C++
53 lines
1.5 KiB
C++
/* -*- c++ -*- ----------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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https://www.lammps.org/, Sandia National Laboratories
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Steve Plimpton, sjplimp@sandia.gov
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Copyright (2003) Sandia Corporation. Under the terms of Contract
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DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
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certain rights in this software. This software is distributed under
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the GNU General Public License.
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See the README file in the top-level LAMMPS directory.
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------------------------------------------------------------------------- */
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#ifndef LMP_TABULAR_FUNCTION_H
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#define LMP_TABULAR_FUNCTION_H
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namespace LAMMPS_NS {
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class TabularFunction {
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public:
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TabularFunction();
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virtual ~TabularFunction();
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void set_values(int, double, double, double *);
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private:
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int size;
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double xmin, xmax, xmaxsq, rdx, vmax;
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double *xs, *ys, *ys1, *ys2, *ys3, *ys4, *ys5, *ys6;
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void set_xrange(double x1, double x2);
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void reset_size(int);
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void initialize();
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public:
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void value(double x, double &y, int ny, double &y1, int ny1)
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{
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double ps = (x - xmin) * rdx;
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int ks = ps + 0.5;
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if (ks > size - 1) ks = size - 1;
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if (ks < 0) ks = 0;
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ps = ps - ks;
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if (ny) y = ((ys3[ks] * ps + ys2[ks]) * ps + ys1[ks]) * ps + ys[ks];
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if (ny1) y1 = (ys6[ks] * ps + ys5[ks]) * ps + ys4[ks];
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}
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double get_xmax() const { return xmax; }
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double get_xmaxsq() const { return xmaxsq; }
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double get_vmax() { return vmax; }
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};
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} // namespace LAMMPS_NS
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#endif
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