spm_cond_units.m
8a186cd82567master

spm_cond_units.m
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			function [y,scale] = spm_cond_units(y,n)
			% Scales numeric arrays by a multiple of 10^n to avoid numerical overflow
			% FORMAT [y,scale] = spm_cond_units(y,n)
			% y - y*scale;
			% n - default 3
			%__________________________________________________________________________
			% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

			% Karl Friston
			% $Id: spm_cond_units.m 6110 2014-07-21 09:36:13Z karl $

			% default n = 1
			%--------------------------------------------------------------------------
			if nargin < 2, n = 1; end

			switch lower(n)

			case{'csd'}

			% normalise to total power
			%------------------------------------------------------------------
			g = 0;
			for i = 1:length(y)
			csd = y{i};
			for j = 1:size(csd,2);
			g = g + sum(csd(:,j,j));
			end
			end
			scale = (length(y)size(csd,1)size(csd,2))/g;
			y = spm_unvec(spm_vec(y)*scale,y);

			otherwise

			% rescale
			%------------------------------------------------------------------
			if isnumeric(y)
			scale = max(max(max(abs(y))))/8;
			scale = (10^n)^-round(log10(scale)/n);
			y = y*scale;
			else
			d = spm_vec(y);
			scale = max(abs(d))/8;
			scale = (10^n)^-round(log10(scale)/n);
			y = spm_unvec(d*scale,y);
			end
			end