tweak: nim scratchpad

wip/nim/samples.nim

@@ -7,20 +7,18 @@ proc pow2(x:float, y:int): float =
 
 proc sine(x: float): float = 
   let n = 100
-  var result = 0.0
+  var acc = 0.0
   for i in 0..n:
     let k = 2*n + 1
     let taylor = pow2(x, k) / float(k)
-    result = result + taylor
-  return result
+    acc = acc + taylor
+  return acc
 
 proc log(x: float): float = 
   var y = x - 1 
-  var result = 0.0
   let n = 1000
   for i in 1..n:
-    let taylor = pow2(-1, n+1) * pow2(y, n) / float(n)
-    let n = 1000
+    let taylor = pow2(-1.0, n+1) * pow2(y, n) / float(n)
     result = result + taylor
   return result
 
@@ -31,4 +29,4 @@ proc normal(): float =
   # see https://en.wikipedia.org/wiki/Box%E2%80%93Muller_transform#Basic_form
 
 
-echo log(1.0)
+echo sine(0.1)

wip/nim/sums/makefile

@@ -0,0 +1,2 @@
+build: sums.nim
+	nim c sums.nim

wip/nim/sums/sums.nim

@@ -0,0 +1,23 @@
+import std/math
+# randomize()
+
+proc factorial(n: int): int = 
+  if n == 0 or n < 0: 
+    return 1
+  else:
+    return n * factorial(n - 1)
+
+proc sine(x: float): float = 
+  let n = 8
+  # ^ Taylor will converge really quickly
+  # notice that the factorial of 17 is 
+  # already pretty gigantic
+  var acc = 0.0
+  for i in 0..n:
+    var k = 2*i + 1
+    var taylor = pow(-1, i.float) * pow(x, k.float) / factorial(k).float 
+    acc = acc + taylor
+  return acc 
+
+# echo factorial(17)
+echo sine(1.0)