/usr/include/kdl/solveri.hpp is in liborocos-kdl-dev 1.3.0+dfsg-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 | // Copyright (C) 2013 Stephen Roderick <kiwi dot net at mac dot com>
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#ifndef	__SOLVERI_HPP
#define	__SOLVERI_HPP
namespace KDL {
/**
 * Solver interface supporting storage and description of the latest error.
 *
 * Error codes: Zero (0) indicates no error, positive error codes indicate more
 * of a warning (e.g. a degraded solution, but motion can continue), and
 * negative error codes indicate failure (e.g. a singularity, and motion
 * can not continue).
 *
 * Error codes between -99 and +99 (inclusive) are reserved for system-wide
 * error codes. Derived classes should use values > +100, and < -100.
 *
 * Example use
 *
 * \code
 * class MySolver : public SolverI
 * {
 * public:
 *    static const int E_CHILDFAILD = xxx;
 *
 *    MySolver(SomeOtherSolver& other);
 *    virtual ~MySolver();
 * 	  int CartToJnt(...);
 *    virtual const char* strError(const int error) const;
 * protected:
 *    SomeOtherSolver& child;
 * };
 *
 * ...
 *
 * int MySolver::CartToJnt(...)
 * {
 *     error = child->SomeCall();
 *     if (E_NOERROR != error) {
 *         error = E_CHILDFAILED;
 *     } else {
 *         ...
 *     }
 *     return error;
 * }
 *
 * const char* MySolver::strError(const int error) const
 * {
 *     if (E_CHILDFAILED == error) return "Child solver failed";
 *     else return SolverI::strError(error);
 * }
 *
 * void someFunc()
 * {
 *     SomeOtherSolver child = new SomeOtherSolver(...);
 *     MySolver parent = new MySolver(child);
 *     ...
 *     int rc = parent->CartToJnt(...);
 *     if (E_NOERROR != rc) {
 *         if (MySolver::E_CHILDFAILED == rc) {
 *             rc = child->getError();
 *             // cope with child failure 'rc'
 *         }
 *     }
 *     ...
 * }
 * \endcode
 */
class SolverI
{
public:
    enum {
	/// Converged but degraded solution (e.g. WDLS with psuedo-inverse singular)
        E_DEGRADED         = +1,
    //! No error
        E_NOERROR          =  0,
    //! Failed to converge
        E_NO_CONVERGE      = -1,
    //! Undefined value (e.g. computed a NAN, or tan(90 degrees) )
        E_UNDEFINED        = -2
    };
	/// Initialize latest error to E_NOERROR
	SolverI() :
			error(E_NOERROR)
	{}
	virtual ~SolverI()
	{}
	/// Return the latest error
	virtual int getError() const { return error; }
	/** Return a description of the latest error
		\return if \a error is known then a description of \a error, otherwise
		"UNKNOWN ERROR"
	*/
	virtual const char* strError(const int error) const
	{
		if (E_NOERROR == error) return "No error";
		else if (E_NO_CONVERGE == error) return "Failed to converge";
		else return "UNKNOWN ERROR";
	}
protected:
	/// Latest error, initialized to E_NOERROR in constructor
	int		error;
};
}	//	namespaces
#endif
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