38 lines
1.0 KiB
C
38 lines
1.0 KiB
C
/*BHEADER**********************************************************************
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* Copyright (c) 2008, Lawrence Livermore National Security, LLC.
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* Produced at the Lawrence Livermore National Laboratory.
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* This file is part of HYPRE. See file COPYRIGHT for details.
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*
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* HYPRE is free software; you can redistribute it and/or modify it under the
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* terms of the GNU Lesser General Public License (as published by the Free
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* Software Foundation) version 2.1 dated February 1999.
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*
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* $Revision$
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***********************************************************************EHEADER*/
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#include "_hypre_struct_ls.h"
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/*--------------------------------------------------------------------------
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* hypre_Log2:
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* This routine returns the integer, floor(log_2(p)).
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* If p <= 0, it returns a -1.
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*--------------------------------------------------------------------------*/
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HYPRE_Int
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hypre_Log2(HYPRE_Int p)
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{
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HYPRE_Int e;
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if (p <= 0)
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return -1;
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e = 0;
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while (p > 1)
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{
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e += 1;
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p /= 2;
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}
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return e;
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}
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