gaussian_rand() -> gaussian_rands(), log_rand() -> log_rands()

examples/fractal_tree.scad

@@ -18,12 +18,12 @@ module leaf(s) {
 module branches(minsize){
     if($parent_size2.x>minsize) {
 		attach(TOP)
-		zrot(gaussian_rand(90,20))
-		zrot_copies(n=floor(log_rand(2,5,4)))
-		zrot(gaussian_rand(0,5))
-		yrot(gaussian_rand(30,10))
+		zrot(gaussian_rands(90,20)[0])
+		zrot_copies(n=floor(log_rands(2,5,4)[0]))
+		zrot(gaussian_rands(0,5)[0])
+		yrot(gaussian_rands(30,10)[0])
 		let(
-			sc = gaussian_rand(0.7,0.05),
+			sc = gaussian_rands(0.7,0.05)[0],
 			s1 = $parent_size.z*sc,
 			s2 = $parent_size2.x
 		)
@@ -32,7 +32,7 @@ module branches(minsize){
 	} else {
 		recolor("springgreen")
 		attach(TOP) zrot(90)
-		leaf(gaussian_rand(100,5));
+		leaf(gaussian_rands(100,5)[0]);
 	}
 }
 recolor("lightgray") cylinder(d1=300, d2=250, l=1500) branches(10);

math.scad

@@ -259,39 +259,49 @@ function log2(x) = ln(x)/ln(2);
 //   min = Minimum integer value to return.
 //   max = Maximum integer value to return.
 //   N = Number of random integers to return.
-//   seed = Random number seed.
+//   seed = If given, sets the random number seed.
 // Example:
 //   ints = rand_int(0,100,3);
 //   int = rand_int(-10,10,1)[0];
-function rand_int(min,max,N,seed=undef) =
+function rand_int(min, max, N, seed=undef) =
 	assert(max >= min, "Max value cannot be smaller than min")
 	let (rvect = is_def(seed) ? rands(min,max+1,N,seed) : rands(min,max+1,N))
 	[for(entry = rvect) floor(entry)];
 
 
-// Function: gaussian_rand()
+// Function: gaussian_rands()
 // Usage:
-//   gaussian_rand(mean, stddev)
+//   gaussian_rands(mean, stddev, [N], [seed])
 // Description:
 //   Returns a random number with a gaussian/normal distribution.
 // Arguments:
 //   mean = The average random number returned.
 //   stddev = The standard deviation of the numbers to be returned.
-function gaussian_rand(mean, stddev) =
-	let(s=rands(0,1,2)) mean + stddev*sqrt(-2*ln(s.x))*cos(360*s.y);
+//   N = Number of random numbers to return.  Default: 1
+//   seed = If given, sets the random number seed.
+function gaussian_rands(mean, stddev, N=1, seed=undef) =
+	let(nums = is_undef(seed)? rands(0,1,N*2) : rands(0,1,N*2,seed))
+	[for (i = list_range(N)) mean + stddev*sqrt(-2*ln(nums[i*2]))*cos(360*nums[i*2+1])];
 
 
-// Function: log_rand()
+// Function: log_rands()
 // Usage:
-//   log_rand(minval, maxval, factor);
+//   log_rands(minval, maxval, factor, [N], [seed]);
 // Description:
 //   Returns a single random number, with a logarithmic distribution.
 // Arguments:
 //   minval = Minimum value to return.
 //   maxval = Maximum value to return.  `minval` <= X < `maxval`.
 //   factor = Log factor to use.  Values of X are returned `factor` times more often than X+1.
-function log_rand(minval, maxval, factor) =
-	-ln(1-rands(1-1/pow(factor,minval), 1-1/pow(factor,maxval), 1)[0])/ln(factor);
+//   N = Number of random numbers to return.  Default: 1
+//   seed = If given, sets the random number seed.
+function log_rands(minval, maxval, factor, N=1, seed=undef) =
+	assert(maxval >= minval, "maxval cannot be smaller than minval")
+	let(
+		minv = 1-1/pow(factor,minval),
+		maxv = 1-1/pow(factor,maxval),
+		nums = is_undef(seed)? rands(minv, maxv, N) : rands(minv, maxv, N, seed)
+	) [for (num=nums) -ln(1-num)/ln(factor)];
 
 
 // Function: segs()

tests/test_math.scad

@@ -168,9 +168,42 @@ module test_log2() {
 test_log2();
 
 
-// TODO: Tests for rand_int()
-// TODO: Tests for gaussian_rand()
-// TODO: Tests for log_rand()
+module test_rand_int() {
+	nums = rand_int(-100,100,1000,seed=2134);
+	assert(len(nums)==1000);
+	for (num = nums) {
+		assert(num>=-100);
+		assert(num<=100);
+		assert(num==floor(num));
+	}
+}
+test_rand_int();
+
+
+module test_gaussian_rands() {
+	nums1 = gaussian_rands(0,10,1000,seed=2132);
+	nums2 = gaussian_rands(0,10,1000,seed=2130);
+	nums3 = gaussian_rands(0,10,1000,seed=2132);
+	assert(len(nums1)==1000);
+	assert(len(nums2)==1000);
+	assert(len(nums3)==1000);
+	assert(nums1==nums3);
+	assert(nums1!=nums2);
+}
+test_gaussian_rands();
+
+
+module test_log_rands() {
+	nums1 = log_rands(0,100,10,1000,seed=2189);
+	nums2 = log_rands(0,100,10,1000,seed=2310);
+	nums3 = log_rands(0,100,10,1000,seed=2189);
+	assert(len(nums1)==1000);
+	assert(len(nums2)==1000);
+	assert(len(nums3)==1000);
+	assert(nums1==nums3);
+	assert(nums1!=nums2);
+}
+test_log_rands();
 
 
 module test_segs() {

version.scad

@@ -8,7 +8,7 @@
 //////////////////////////////////////////////////////////////////////
 
 
-BOSL_VERSION = [2,0,9];
+BOSL_VERSION = [2,0,10];
 
 
 // Section: BOSL Library Version Functions