added rand as new function

@GRIDobj/rand.m

@@ -0,0 +1,88 @@
+function Z = rand(DEM,dist,params)
+
+%RAND Compute a GRIDobj with random numbers
+%
+% Syntax
+%
+% Z = rand(A)
+% Z = rand(A,'unif',[ll ul])
+% Z = rand(A,'normal', [mu sigma])
+% Z = rand(A,'randperm')
+% Z = rand(A,'randi',[ll ul])
+% Z = rand(A,pd)
+%
+% Description
+%
+% rand returns a GRIDobj of random numbers. The raster has the same
+% dimensions and coordinates as the GRIDobj A. 
+% 
+% rand(A,'unif',[ll ul]) returns uniform distributed numbers between
+% ll and ul.
+%
+% rand(A,'normal', [mu sigma]) returns normal distributed random 
+% numbers with average mu and standard deviation sigma.
+%
+% rand(A,'randperm') return a random permutation of integers in the 
+% range of 1:prod(A.size).
+%
+% rand(A,'randi',[ll ul]) returns random integer values between ll and
+% ul.
+% 
+% rand(A,pd) returns random numbers from the distribution defined by
+% pd (see makedist and fitdist).
+%
+% Input arguments
+%
+% A GRIDobj
+% ll,ul lower and upper limits of random numbers.
+%
+% Output arguments
+%
+% Z GRIDobj
+%
+%
+% See also: GRIDobj
+% 
+% Author: Wolfgang Schwanghart (w.schwanghart[at]geo.uni-potsdam.de)
+% Date: 31. May, 2022
+
+
+
+if nargin == 1
+ Z = GRIDobj(DEM);
+ Z.Z = rand(DEM.size);
+else
+ if ischar(dist) || isstring(dist)
+ switch lower(dist)
+ case 'unif'
+ Z = GRIDobj(DEM);
+ Z.Z = rand(DEM.size);
+ if nargin == 3
+ Z.Z = Z.Z .* diff(params);
+ Z.Z = Z.Z + params(1);
+ end
+ case {'normal','randn'}
+
+ Z = GRIDobj(DEM);
+ Z.Z = randn(DEM.size);
+ if nargin == 3
+ Z.Z = Z.Z * params(2) + params(1);
+ end
+ case 'randperm'
+ Z = GRIDobj(DEM);
+ Z.Z = reshape(randperm(prod(DEM.size)),DEM.size(1),DEM.size(2));
+ case 'randi'
+ if nargin == 2
+ params = [1 prod(DEM.size)];
+ end
+ Z = GRIDobj(DEM);
+ Z.Z = randi(diff(params),DEM.size) + params(1);
+ end
+ else
+ Z = GRIDobj(DEM);
+ Z.Z = random(dist,DEM.size);
+ end
+end
+
+
+

readme.md

@@ -128,6 +128,7 @@ resource for code and examples is the [TopoToolbox blog](https://topotoolbox.word
 - new function: private in FLOWobj graydistparallel
 - new function: GRIDobj/diffusion
 - new function: GRIDobj/histogram
+- new function: GRIDobj/rand
 - new function: PPS/extractvaluesaroundpoints
 - new function: STREAMobj/extend2divide
 - new function: STREAMobj/binarize