1.0.8: Fix and bench isNan.

src/vmath.nim

@@ -424,10 +424,9 @@ proc toDegrees*[T: SomeFloat](rad: T): T =
   ## Convert radians to degrees.
   return fixAngle(180.0 * rad / PI)
 
-proc isNaN*(n: SomeFloat): bool =
-  ## Returns true if number is a Nan.
-  n.classify != fcNan
-
+proc isNaN*(x: float32): bool =
+  ## Returns true if number is a NaN.
+  x != 0.0 and (x != x or x * 0.5 == x)
 template genConstructor(lower, upper, typ: untyped) =
 
   proc `lower 2`*(): `upper 2` = gvec2[typ](typ(0), typ(0))

tests/bench_isNan.nim

@@ -0,0 +1,124 @@
+import benchy, vmath
+
+proc isNaNSlow(f: SomeFloat): bool =
+  ## Returns true if number is a NaN.
+  f.classify notin {fcNormal, fcZero, fcSubnormal}
+
+proc isNaNRyan(x: SomeFloat): bool =
+  if x == 0.0:
+    return false
+  x != x or x * 0.5 == x
+
+proc isNaN3*(x: SomeFloat): bool =
+  ## Returns true if number is a NaN.
+  x != 0.0 and (x != x or x * 0.5 == x)
+
+assert isNaNSlow(0.3) == false
+assert isNaNSlow(0.0) == false
+assert isNaNSlow(0.3/0.0) == true
+assert isNaNSlow(-0.3/0.0) == true
+assert isNaNSlow(5.0e-324) == false
+
+assert isNaNRyan(0.3) == false
+assert isNaNRyan(0.0) == false
+assert isNaNRyan(0.3/0.0) == true
+assert isNaNRyan(-0.3/0.0) == true
+assert isNaNRyan(5.0e-324) == false
+
+assert isNan(float32(0.3)) == false
+assert isNan(float32(0.0)) == false
+assert isNan(float32(0.3/0.0)) == true
+assert isNan(float32(-0.3/0.0)) == true
+assert isNan(float32(5.0e-324)) == false
+
+assert isNan(float64(0.3)) == false
+assert isNan(float64(0.0)) == false
+assert isNan(float64(0.3/0.0)) == true
+assert isNan(float64(-0.3/0.0)) == true
+assert isNan(float64(5.0e-324)) == false
+
+assert isNan3(float32(0.3)) == false
+assert isNan3(float32(0.0)) == false
+assert isNan3(float32(0.3/0.0)) == true
+assert isNan3(float32(-0.3/0.0)) == true
+assert isNan3(float32(5.0e-324)) == false
+
+assert isNan3(float64(0.3)) == false
+assert isNan3(float64(0.0)) == false
+assert isNan3(float64(0.3/0.0)) == true
+assert isNan3(float64(-0.3/0.0)) == true
+assert isNan3(float64(5.0e-324)) == false
+
+const num = 1_00_000
+
+timeIt "isNaNSlow float32":
+  var x: float32
+  var n = 0
+  for i in 0 .. num:
+    if x.isNaNSlow:
+      n += 1
+    x = float32(i) / float32(i)
+  keep n
+
+timeIt "isNaNSlow float64":
+  var x: float64
+  var n = 0
+  for i in 0 .. num:
+    if x.isNaNSlow:
+      n += 1
+    x = float64(i) / float64(i)
+  keep n
+
+timeIt "isNaNRyan float32":
+  var x: float32
+  var n = 0
+  for i in 0 .. num:
+    if x.isNaNRyan:
+      n += 1
+    x = float32(i) / float32(i)
+  keep n
+
+timeIt "isNaNRyan float64":
+  var x: float64
+  var n = 0
+  for i in 0 .. num:
+    if x.isNaNRyan:
+      n += 1
+    x = float64(i) / float64(i)
+  keep n
+
+timeIt "isNan float32":
+  var x: float32
+  var n = 0
+  for i in 0 .. num:
+    if x.isNan:
+      n += 1
+    x = float32(i) / float32(i)
+  keep n
+
+timeIt "isNan float64":
+  var x: float64
+  var n = 0
+  for i in 0 .. num:
+    if x.isNan:
+      n += 1
+    x = float64(i) / float64(i)
+  keep n
+
+timeIt "isNan3 float32":
+  var x: float32
+  var n = 0
+  for i in 0 .. num:
+    if x.isNan3:
+      n += 1
+    x = float32(i) / float32(i)
+  keep n
+
+timeIt "isNan3 float64":
+  var x: float64
+  var n = 0
+  for i in 0 .. num:
+    if x.isNan3:
+      n += 1
+    x = float64(i) / float64(i)
+  keep n

tests/test.nim

@@ -82,8 +82,27 @@ block:
   doAssert turnAngle(0.0, PI, 0.5) ~= 0.5
   doAssert turnAngle(0.5, PI, 3.5) ~= PI
 
-  var anum = 1.0 / 0.0
-  doAssert anum.isNan == true
+  proc isNaNSlow(f: SomeFloat): bool =
+    ## Returns true if number is a NaN.
+    f.classify notin {fcNormal, fcZero, fcSubnormal}
+
+  assert isNaNSlow(0.3) == false
+  assert isNaNSlow(0.0) == false
+  assert isNaNSlow(0.3/0.0) == true
+  assert isNaNSlow(-0.3/0.0) == true
+  assert isNaNSlow(5.0e-324) == false
+
+  assert isNan(float32(0.3)) == false
+  assert isNan(float32(0.0)) == false
+  assert isNan(float32(0.3/0.0)) == true
+  assert isNan(float32(-0.3/0.0)) == true
+  assert isNan(float32(5.0e-324)) == false
+
+  assert isNan(float64(0.3)) == false
+  assert isNan(float64(0.0)) == false
+  assert isNan(float64(0.3/0.0)) == true
+  assert isNan(float64(-0.3/0.0)) == true
+  assert isNan(float64(5.0e-324)) == false
 
 block:
   # Test vec2 cast.

vmath.nimble

@@ -1,4 +1,4 @@
-version       = "1.0.7"
+version       = "1.0.8"
 author        = "treeform"
 description   = "Your single stop for vector math routines for 2d and 3d graphics."
 license       = "MIT"