Date: 2022-11-02T11:47:50+00:00

Actual source code: slepcmath.h
slepc-3.18.1 2022-11-02
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */
     10: /*
     11:    SLEPc mathematics include file. Defines basic operations and functions.
     12:    This file is included by slepcsys.h and should not be used directly.
     13: */

     15: #if !defined(SLEPCMATH_H)
     16: #define SLEPCMATH_H

     18: /* SUBMANSEC = sys */

     20: /*
     21:     Default tolerance for the different solvers, depending on the precision
     22: */
     23: #if defined(PETSC_USE_REAL_SINGLE)
     24: #  define SLEPC_DEFAULT_TOL   1e-5
     25: #elif defined(PETSC_USE_REAL_DOUBLE)
     26: #  define SLEPC_DEFAULT_TOL   1e-8
     27: #elif defined(PETSC_USE_REAL___FLOAT128)
     28: #  define SLEPC_DEFAULT_TOL   1e-16
     29: #elif defined(PETSC_USE_REAL___FP16)
     30: #  define SLEPC_DEFAULT_TOL   1e-2
     31: #endif

     33: #define SlepcDefaultTol(tol) (((tol)==PETSC_DEFAULT)?SLEPC_DEFAULT_TOL:(tol))

     35: /*@C
     36:    SlepcAbs - Returns sqrt(x**2+y**2), taking care not to cause unnecessary
     37:    overflow. It is based on LAPACK's DLAPY2.

     39:    Not Collective

     41:    Input parameters:
     42: .  x,y - the real numbers

     44:    Output parameter:
     45: .  return - the result

     47:    Note:
     48:    This function is not available from Fortran.

     50:    Level: developer
     51: @*/
     52: static inline PetscReal SlepcAbs(PetscReal x,PetscReal y)
     53: {
     54:   PetscReal w,z,t,xabs=PetscAbs(x),yabs=PetscAbs(y);

     56:   w = PetscMax(xabs,yabs);
     57:   z = PetscMin(xabs,yabs);
     58:   if (PetscUnlikely(z == 0.0)) return w;
     59:   t = z/w;
     60:   return w*PetscSqrtReal(1.0+t*t);
     61: }

     63: /*MC
     64:    SlepcAbsEigenvalue - Returns the absolute value of a complex number given
     65:    its real and imaginary parts.

     67:    Synopsis:
     68:    PetscReal SlepcAbsEigenvalue(PetscScalar x,PetscScalar y)

     70:    Not Collective

     72:    Input parameters:
     73: +  x  - the real part of the complex number
     74: -  y  - the imaginary part of the complex number

     76:    Notes:
     77:    This function computes sqrt(x**2+y**2), taking care not to cause unnecessary
     78:    overflow. It is based on LAPACK's DLAPY2.

     80:    In complex scalars, only the first argument is used.

     82:    This function is not available from Fortran.

     84:    Level: developer
     85: M*/
     86: #if !defined(PETSC_USE_COMPLEX)
     87: #define SlepcAbsEigenvalue(x,y) SlepcAbs(x,y)
     88: #else
     89: #define SlepcAbsEigenvalue(x,y) PetscAbsScalar(x)
     90: #endif

     92: #endif

     94: /*
     95:    SlepcSetFlushToZero - Set the FTZ flag in floating-point arithmetic.
     96: */
     97: static inline PetscErrorCode SlepcSetFlushToZero(unsigned int *state)
     98: {
     99: #if defined(PETSC_HAVE_XMMINTRIN_H) && defined(_MM_FLUSH_ZERO_ON) && defined(__SSE__)
    100:   *state = _MM_GET_FLUSH_ZERO_MODE();
    101:   _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
    102: #else
    103:   *state = 0;
    104: #endif
    105:   return 0;
    106: }

    108: /*
    109:    SlepcResetFlushToZero - Reset the FTZ flag in floating-point arithmetic.
    110: */
    111: static inline PetscErrorCode SlepcResetFlushToZero(unsigned int *state)
    112: {
    113: #if defined(PETSC_HAVE_XMMINTRIN_H) && defined(_MM_FLUSH_ZERO_MASK) && defined(__SSE__)
    114:   _MM_SET_FLUSH_ZERO_MODE(*state & _MM_FLUSH_ZERO_MASK);
    115: #else
    116:   *state = 0;
    117: #endif
    118:   return 0;
    119: }