Fix erf and a few other improvements (#582)

* Fix `erf`

* [NFC] Semicolon cleanup

* Test proper type

Author: christiangnrd

ext/SpecialFunctionsExt.jl

@@ -71,9 +71,14 @@ Metal.@device_override function SpecialFunctions.erf(x::Float32)
                 if ix < 0x04000000 	# |x|<0x1p-119
                     return (8 * x + efx8 * x) / 8	# avoid spurious underflow
                 end
-                return x + efx*x;
+                return x + efx*x
             end
         end
+        z = x * x
+        r = pp0 + z * (pp1 + z * pp2)
+        s = 1.0f0 + z * (qq1 + z * (qq2 + z * qq3))
+	    y = r / s
+	    return x + x*y
     end
 
     if ix < 0x3fa00000 	# 0.84375 <= |x| < 1.25
@@ -152,15 +157,15 @@ Metal.@device_override function SpecialFunctions.erfc(x::Float32)
         Q = 1.0f0 + s * (qa1 + s * (qa2 + s * (qa3 + s * qa4)))
         if hx >= 0
             z = 1.0f0 - erx
-            return z - P / Q;
+            return z - P / Q
         else
             z = erx + P / Q
             return 1.0f0 + z
         end
     end
 
     if ix < 0x41300000	# |x|<28
-        x = abs(x);
+        x = abs(x)
         s = 1.0f0 / (x * x)
         if ix < 0x4036DB6D	# |x| < 1/.35 ~ 2.857143
             R = ra0 + s * (ra1 + s * (ra2 + s * ra3))

test/device/intrinsics/math.jl

@@ -237,38 +237,38 @@ end
     end
 
     let # log1p
-        arr = collect(LinRange(nextfloat(-1.0f0), 10.0f0, 20))
+        arr = T.(collect(LinRange(nextfloat(-1.0f0), 10.0f0, 20)))
         buffer = MtlArray(arr)
-        vec = Array(log1p.(buffer))
-        @test vec ≈ log1p.(arr)
+        cpures = log1p.(arr)
+        @test Array(log1p.(buffer)) ≈ log1p.(arr)
     end
 
     let # erf
-        arr = collect(LinRange(nextfloat(-3.0f0), 3.0f0, 20))
+        arr = T[-1.0, -0.5, 0.0, 1.0e-3, 1.0, 2.0, 5.5]
         buffer = MtlArray(arr)
-        vec = Array(SpecialFunctions.erf.(buffer))
-        @test vec ≈ SpecialFunctions.erf.(arr)
+        cpures = SpecialFunctions.erf.(arr)
+        @test Array(SpecialFunctions.erf.(buffer)) ≈ cpures broken = (T == Float16)
     end
 
     let # erfc
-        arr = collect(LinRange(nextfloat(-3.0f0), 3.0f0, 20))
+        arr = T.(collect(LinRange(nextfloat(-3.0f0), 3.0f0, 20)))
         buffer = MtlArray(arr)
-        vec = Array(SpecialFunctions.erfc.(buffer))
-        @test vec ≈ SpecialFunctions.erfc.(arr)
+        cpures = SpecialFunctions.erfc.(arr)
+        @test Array(SpecialFunctions.erfc.(buffer)) ≈ cpures broken = (T == Float16)
     end
 
     let # erfinv
-        arr = collect(LinRange(-1.0f0, 1.0f0, 20))
+        arr = T.(collect(LinRange(-1.0f0, 1.0f0, 20)))
         buffer = MtlArray(arr)
-        vec = Array(SpecialFunctions.erfinv.(buffer))
-        @test vec ≈ SpecialFunctions.erfinv.(arr)
+        cpures = SpecialFunctions.erfinv.(arr)
+        @test Array(SpecialFunctions.erfinv.(buffer)) ≈ cpures
     end
 
     let # expm1
-        arr = collect(LinRange(nextfloat(-88.0f0), 88.0f0, 100))
+        arr = T.(collect(LinRange(nextfloat(-88.0f0), 88.0f0, 100)))
         buffer = MtlArray(arr)
-        vec = Array(expm1.(buffer))
-        @test vec ≈ expm1.(arr)
+        cpures = expm1.(arr)
+        @test Array(expm1.(buffer)) ≈ cpures
     end
 
 

test/mps/ndarray.jl

@@ -1,7 +1,7 @@
 #
 # matrix descriptor
 #
-using Metal,Test;
+using Metal
 using .MPS: MPSNDArrayDescriptor, MPSDataType, lengthOfDimension, descriptor, resourceSize
 @static if Metal.macos_version() >= v"15"
     using .MPS: userBuffer