Added function to compute tight grid of non missing data in matrices

tighten.m

+function [Value,gv] = tighten(Value,varargin)
+%TIGHTEN Summary of this function goes here
+%   Detailed explanation goes here
+
+if nargin>1
+    Mask = varargin{1};
+elseif islogical(Value)
+    Mask = Value;
+else
+    Mask = ~isnan(Value);
+end
+
+numdims = ndims(Mask);
+gv = cell(1,numdims);
+for dim = 1:numdims
+    M = any(Mask,setdiff(1:numdims,dim));
+    gv{dim} = find(M,1,'first'):find(M,1,'last');
+end
+
+Value = Value(gv{:});
+
+end
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