C++*******************************************************************
C
C $$ LOG2.FOR
C
C **********************************************************************
C=* *
C=* This file is part of: SPIDER - Modular Image Processing System. *
C=* SPIDER System Authors: Joachim Frank & ArDean Leith *
C=* Copyright 1985-2010 Health Research Inc., *
C=* Riverview Center, 150 Broadway, Suite 560, Menands, NY 12204. *
C=* Email: spider@wadsworth.org *
C=* *
C=* SPIDER is free software; you can redistribute it and/or *
C=* modify it under the terms of the GNU General Public License as *
C=* published by the Free Software Foundation; either version 2 of the *
C=* License, or (at your option) any later version. *
C=* *
C=* SPIDER is distributed in the hope that it will be useful, *
C=* but WITHOUT ANY WARRANTY; without even the implied warranty of *
C=* merchantability or fitness for a particular purpose. See the GNU *
C=* General Public License for more details. *
C=* You should have received a copy of the GNU General Public License *
C=* along with this program. If not, see *
C=* *
C **********************************************************************
C
C
C $$ LOG2: RETURNS THE SMALLEST POWER BY WHICH 2 HAS TO BE
C RAISED TO OBTAIN AN INTEGER .GE.M
C ONLY DEFINED FOR M.GE.1 !
C
C FUNCTION LOG2(M)
C
C--*******************************************************************
C
C
FUNCTION LOG2(M)
LOG2 = 0
I=1
DO K=1,100000
IF(I.GE.M) RETURN
I = I*2
LOG2 = LOG2+1
ENDDO
END