ST_d2phi

 Convert sediment diameter (m) to phi 

 function [phi] = ST_d2phi(d)

 DESCRIPTION:
    Convert a sediment grain size in m to phi 

 INPUT:
    d: sediment grain size in m

 OUTPUT:
    phi: sediment grain size in phi scale

 EXAMPLE USAGE
    phi = ST_d2phi(.001)

 Author(s):  
    Geoff Cowles (University of Massachusetts Dartmouth)

 Revision history
   
==============================================================================

0001 function [phi] = ST_d2phi(d)
0002 % Convert sediment diameter (m) to phi
0003 %
0004 % function [phi] = ST_d2phi(d)
0005 %
0006 % DESCRIPTION:
0007 %    Convert a sediment grain size in m to phi
0008 %
0009 % INPUT:
0010 %    d: sediment grain size in m
0011 %
0012 % OUTPUT:
0013 %    phi: sediment grain size in phi scale
0014 %
0015 % EXAMPLE USAGE
0016 %    phi = ST_d2phi(.001)
0017 %
0018 % Author(s):
0019 %    Geoff Cowles (University of Massachusetts Dartmouth)
0020 %
0021 % Revision history
0022 %
0023 %==============================================================================
0024 
0025 %subname = 'ST_d2phi';
0026 %fprintf('\n')
0027 %fprintf(['begin : ' subname '\n'])
0028 
0029 %------------------------------------------------------------------------------
0030 % calculate phi
0031 %------------------------------------------------------------------------------
0032 phi = -log2(d*1000);
0033 
0034 %fprintf(['end   : ' subname '\n'])