Date: 2015-10-02T22:21:03+00:00

Actual source code: nashimpl.h
petsc-3.6.2 2015-10-02
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      1: /*****************************************************************************/
      2: /* Context for using preconditioned conjugate gradient method to minimized a */
      3: /* quadratic function subject to a trust region constraint.  If the matrix   */
      4: /* is indefinite, a direction of negative curvature may be encountered.  If  */
      5: /* a direction of negative curvature is found during the first iteration,    */
      6: /* then it is a preconditioned gradient direction and we follow it to the    */
      7: /* boundary of the trust region.  If a direction of negative curvature is    */
      8: /* encountered on subsequent iterations, then we terminate the algorithm.    */
      9: /*                                                                           */
     10: /* This method is described in:                                              */
     11: /*   S. Nash, "Newton-type Minimization via the Lanczos Method", SIAM        */
     12: /*     Journal on Numerical Analysis, 21, pages 553-572, 1984.               */
     13: /*****************************************************************************/

     18: typedef struct {
     19:   PetscReal radius;
     20:   PetscReal norm_d;
     21:   PetscReal o_fcn;
     22:   PetscInt  dtype;
     23: } KSP_NASH;

     25: #endif