[simulations] added uniform distribution

simulations/code/exprandom.m

@@ -1,8 +1,8 @@
-n = 10000;
-lambda = 50.0;                 % event rate
-t = exprnd(1.0/lambda, n, 1);  % exponentially distributed random numbers
-m = mean(t);                   % mean time interval
-s = std(t);                    % corresponding standard deviation
-fprintf('Generated n=%d exponentially distributed random time intervals\n', n);
-fprintf('  with rate=%.0fHz (-> mean=%.3fs, std=%.3fs)\n', lambda, 1.0/lambda, 1.0/lambda);
-fprintf('Measured mean=%.3fs, std=%.3fs\n', m, s);
+n = 200;                     % number of time intervals
+rate = 50.0;                 % event rate
+t = exprnd(1.0/rate, n, 1);  % exponentially distributed intervals
+m = mean(t);                 % mean time interval
+s = std(t);                  % corresponding standard deviation
+fprintf('Generated n=%d random time intervals with rate=%.0fHz:\n', n, rate);
+fprintf('  Expected mean interval=%.3fs, std=%.3fs\n', 1.0/rate, 1.0/rate);
+fprintf('  Measured mean interval=%.3fs, std=%.3fs\n', m, s);

simulations/code/exprandom.out

@@ -1,3 +1,3 @@
-Generated n=10000 exponentially distributed random time intervals
-  with rate=50Hz (-> mean=0.020s, std=0.020s)
-Measured mean=0.020s, std=0.020s
+Generated n=200 random time intervals with rate=50Hz:
+  Expected mean interval=0.020s, std=0.020s
+  Measured mean interval=0.020s, std=0.019s

simulations/code/unirandom.m

@@ -0,0 +1,16 @@
+n = 10000;                    % number of action potentials
+T = 100.0;                    % total time interval
+spikes = sort(T*rand(n, 1));  % sorted times of action potentials
+isis = diff(spikes);          % interspike intervals
+rate = n/T;                   % firing rate
+misi = mean(isis);            % mean interspike interval
+sisi = std(isis);             % and standard deviation
+fprintf('firing rate = %.1fHz\n', rate);
+fprintf('   mean ISI = %.1fms\n', 1000.0*misi);  % inverse of rate
+fprintf('    std ISI = %.1fms\n', 1000.0*sisi);  % same as mean
+hist(1000.0*isis, 50);        % exponential distribution
+xlabel('ISI [ms]');
+ylabel('count');
+
+
+

simulations/code/unirandom.out

@@ -0,0 +1,3 @@
+firing rate = 100.0Hz
+   mean ISI = 10.0ms
+    std ISI = 10.0ms