Add test for deterministic -> stochastic

Author: pjaap

test/conversions.jl

@@ -1,7 +1,7 @@
-@testset "Converting Stochastic FP to BFloat16sr" begin
+@testset "Deterministic conversion of Stochastic FP to BFloat16sr" begin
     for k in 1:100000
         trueVal = randn(Float64)
-        # Convert to each deterministic type to ensure the result is 
+        # Convert to each deterministic type to ensure the result is
         # representable in all precisions
         trueVal=Float16(Float32(BFloat16(trueVal)))
         bfloatVal = BFloat16sr(trueVal)
@@ -14,10 +14,10 @@
     end
 end
 
-@testset "Converting Stochastic FP to Float16sr" begin
+@testset "Deterministic conversion of  Stochastic FP to Float16sr" begin
     for k in 1:100000
         trueVal = randn(Float64)
-        # Convert to each deterministic type to ensure the result is 
+        # Convert to each deterministic type to ensure the result is
         # representable in all precisions
         trueVal=Float16(Float32(BFloat16(trueVal)))
         bfloatVal = BFloat16sr(trueVal)
@@ -30,10 +30,10 @@ end
     end
 end
 
-@testset "Converting Stochastic FP to Float32sr" begin
+@testset "Deterministic conversion of  Stochastic FP to Float32sr" begin
     for k in 1:100000
         trueVal = randn(Float64)
-        # Convert to each deterministic type to ensure the result is 
+        # Convert to each deterministic type to ensure the result is
         # representable in all precisions
         trueVal=Float16(Float32(BFloat16(trueVal)))
         bfloatVal = BFloat16sr(trueVal)
@@ -45,3 +45,37 @@ end
         @test float32Val == Float32sr(float16Val)
     end
 end
+
+
+
+for SR in [Float16sr, BFloat16sr, Float32sr]
+
+    # corresponding FP type
+    FP = float(SR)
+
+    @eval begin
+        @testset "Stochastic conversion of Float64 to $(nameof($SR))" begin
+            for k in 1:100
+                trueVal = randn(Float64)
+
+                # make sure that this is not representable by FP
+                if trueVal == $FP(trueVal)
+                    trueVal = nextfloat(trueVal)
+                end
+
+                roundedVal = $SR(trueVal)
+
+                # check that rounding is not deterministic
+                is_stochastic = false
+                for l in 1:10000
+                    if roundedVal != $SR(trueVal)
+                        is_stochastic = true
+                        break
+                    end
+                end
+
+                @test is_stochastic == true
+            end
+        end
+    end
+end