mandel_test.go

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // This benchmark, taken from the shootuot, tests floating point performance.
     6  
     7  package go1
     8  
     9  import "testing"
    10  
    11  func mandelbrot(n int) int {
    12  	const Iter = 50
    13  	const Zero float64 = 0
    14  	const Limit = 2.0
    15  	ok := 0
    16  	for y := 0; y < n; y++ {
    17  		for x := 0; x < n; x++ {
    18  			Zr, Zi, Tr, Ti := Zero, Zero, Zero, Zero
    19  			Cr := (2*float64(x)/float64(n) - 1.5)
    20  			Ci := (2*float64(y)/float64(n) - 1.0)
    21  
    22  			for i := 0; i < Iter && (Tr+Ti <= Limit*Limit); i++ {
    23  				Zi = 2*Zr*Zi + Ci
    24  				Zr = Tr - Ti + Cr
    25  				Tr = Zr * Zr
    26  				Ti = Zi * Zi
    27  			}
    28  
    29  			if Tr+Ti <= Limit*Limit {
    30  				ok++
    31  			}
    32  		}
    33  	}
    34  	return ok
    35  }
    36  
    37  func BenchmarkMandelbrot200(b *testing.B) {
    38  	for i := 0; i < b.N; i++ {
    39  		mandelbrot(200)
    40  	}
    41  }
    42
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