From: Rob Pike Date: Fri, 6 Feb 2009 23:03:14 +0000 (-0800) Subject: powser cleanup. X-Git-Tag: weekly.2009-11-06~2219 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=ee9b5a15a145494d574984855a3afe301246c9b8;p=gostls13.git powser cleanup. - don't need *struct - don't need item/rat both - closures make the inner slaves easier - delete some old BUG comments powser2 is left mostly alone, for variety. R=rsc DELTA=134 (2 added, 20 deleted, 112 changed) OCL=24579 CL=24581 --- diff --git a/test/chan/powser1.go b/test/chan/powser1.go index 3334660918..c167da1927 100644 --- a/test/chan/powser1.go +++ b/test/chan/powser1.go @@ -17,21 +17,19 @@ type rat struct { num, den int64; // numerator, denominator } -type item *rat; - -func (u *rat) pr(){ +func (u rat) pr() { if u.den==1 { print(u.num) } else { print(u.num, "/", u.den) } print(" ") } -func (u *rat) eq(c item) bool { +func (u rat) eq(c rat) bool { return u.num == c.num && u.den == c.den } type dch struct { req chan int; - dat chan item; + dat chan rat; nam int; } @@ -48,7 +46,7 @@ func mkdch() *dch { chnameserial++; d := new(dch); d.req = make(chan int); - d.dat = make(chan item); + d.dat = make(chan rat); d.nam = c; return d; } @@ -62,8 +60,8 @@ func mkdch2() *dch2 { // split reads a single demand channel and replicates its // output onto two, which may be read at different rates. -// A process is created at first demand for an item and dies -// after the item has been sent to both outputs. +// A process is created at first demand for a rat and dies +// after the rat has been sent to both outputs. // When multiple generations of split exist, the newest // will service requests on one channel, which is @@ -74,7 +72,7 @@ func mkdch2() *dch2 { // a signal on the release-wait channel tells the next newer // generation to begin servicing out[1]. -func dosplit(in *dch, out *dch2, wait chan int ){ +func dosplit(in *dch, out *dch2, wait chan int ) { var t *dch; both := false; // do not service both channels @@ -105,33 +103,33 @@ func dosplit(in *dch, out *dch2, wait chan int ){ release <- 0; } -func split(in *dch, out *dch2){ +func split(in *dch, out *dch2) { release := make(chan int); go dosplit(in, out, release); release <- 0; } -func put(dat item, out *dch){ +func put(dat rat, out *dch) { <-out.req; out.dat <- dat; } -func get(in *dch) *rat { +func get(in *dch) rat { seqno++; in.req <- seqno; return <-in.dat; } -// Get one item from each of n demand channels +// Get one rat from each of n demand channels -func getn(in []*dch, n int) []item { - // BUG n:=len(in); +func getn(in []*dch) []rat { + n := len(in); if n != 2 { panic("bad n in getn") }; req := new([2] chan int); - dat := new([2] chan item); - out := make([]item, 2); + dat := new([2] chan rat); + out := make([]rat, 2); var i int; - var it item; + var it rat; for i=0; i0; n-- { seqno++; - select{ + select { case req[0] <- seqno: dat[0] = in[0].dat; req[0] = nil; @@ -157,20 +155,20 @@ func getn(in []*dch, n int) []item { return out; } -// Get one item from each of 2 demand channels +// Get one rat from each of 2 demand channels -func get2(in0 *dch, in1 *dch) []item { - return getn([]*dch{in0, in1}, 2); +func get2(in0 *dch, in1 *dch) []rat { + return getn([]*dch{in0, in1}); } -func copy(in *dch, out *dch){ +func copy(in *dch, out *dch) { for { <-out.req; out.dat <- get(in); } } -func repeat(dat item, out *dch){ +func repeat(dat rat, out *dch) { for { put(dat, out) } @@ -198,7 +196,7 @@ func mkPS2() *dch2 { // Integer gcd; needed for rational arithmetic -func gcd (u, v int64) int64{ +func gcd (u, v int64) int64 { if u < 0 { return gcd(-u, v) } if u == 0 { return v } return gcd(v%u, u) @@ -206,9 +204,9 @@ func gcd (u, v int64) int64{ // Make a rational from two ints and from one int -func i2tor(u, v int64) *rat{ +func i2tor(u, v int64) rat { g := gcd(u,v); - r := new(rat); + var r rat; if v > 0 { r.num = u/g; r.den = v/g; @@ -219,54 +217,54 @@ func i2tor(u, v int64) *rat{ return r; } -func itor(u int64) *rat{ +func itor(u int64) rat { return i2tor(u, 1); } -var zero *rat; -var one *rat; +var zero rat; +var one rat; // End mark and end test -var finis *rat; +var finis rat; -func end(u *rat) int64 { +func end(u rat) int64 { if u.den==0 { return 1 } return 0 } // Operations on rationals -func add(u, v *rat) *rat { +func add(u, v rat) rat { g := gcd(u.den,v.den); return i2tor(u.num*(v.den/g)+v.num*(u.den/g),u.den*(v.den/g)); } -func mul(u, v *rat) *rat{ +func mul(u, v rat) rat { g1 := gcd(u.num,v.den); g2 := gcd(u.den,v.num); - r := new(rat); - r.num =(u.num/g1)*(v.num/g2); + var r rat; + r.num = (u.num/g1)*(v.num/g2); r.den = (u.den/g2)*(v.den/g1); return r; } -func neg(u *rat) *rat{ +func neg(u rat) rat { return i2tor(-u.num, u.den); } -func sub(u, v *rat) *rat{ +func sub(u, v rat) rat { return add(u, neg(v)); } -func inv(u *rat) *rat{ // invert a rat +func inv(u rat) rat { // invert a rat if u.num == 0 { panic("zero divide in inv") } return i2tor(u.den, u.num); } // print eval in floating point of PS at x=c to n terms -func Evaln(c *rat, U PS, n int) +func evaln(c rat, U PS, n int) { xn := float64(1); x := float64(c.num)/float64(c.den); @@ -283,7 +281,7 @@ func Evaln(c *rat, U PS, n int) } // Print n terms of a power series -func Printn(U PS, n int){ +func printn(U PS, n int) { done := false; for ; !done && n>0; n-- { u := get(U); @@ -293,12 +291,8 @@ func Printn(U PS, n int){ print(("\n")); } -func Print(U PS){ - Printn(U,1000000000); -} - // Evaluate n terms of power series U at x=c -func eval(c *rat, U PS, n int) *rat{ +func eval(c rat, U PS, n int) rat { if n==0 { return zero } y := get(U); if end(y) != 0 { return zero } @@ -311,17 +305,17 @@ func eval(c *rat, U PS, n int) *rat{ // Make a pair of power series identical to a given power series -func Split(U PS) *dch2{ +func Split(U PS) *dch2 { UU := mkdch2(); go split(U,UU); return UU; } // Add two power series -func Add(U, V PS) PS{ +func Add(U, V PS) PS { Z := mkPS(); - go func(U, V, Z PS){ - var uv [] *rat; + go func() { + var uv []rat; for { <-Z.req; uv = get2(U,V); @@ -338,14 +332,14 @@ func Add(U, V PS) PS{ Z.dat <- finis; } } - }(U, V, Z); + }(); return Z; } // Multiply a power series by a constant -func Cmul(c *rat,U PS) PS{ +func Cmul(c rat,U PS) PS { Z := mkPS(); - go func(c *rat, U, Z PS){ + go func() { done := false; for !done { <-Z.req; @@ -354,34 +348,34 @@ func Cmul(c *rat,U PS) PS{ else { Z.dat <- mul(c,u) } } Z.dat <- finis; - }(c, U, Z); + }(); return Z; } // Subtract -func Sub(U, V PS) PS{ +func Sub(U, V PS) PS { return Add(U, Cmul(neg(one), V)); } // Multiply a power series by the monomial x^n -func Monmul(U PS, n int) PS{ +func Monmul(U PS, n int) PS { Z := mkPS(); - go func(n int, U PS, Z PS){ + go func() { for ; n>0; n-- { put(zero,Z) } copy(U,Z); - }(n, U, Z); + }(); return Z; } // Multiply by x -func Xmul(U PS) PS{ +func Xmul(U PS) PS { return Monmul(U,1); } -func Rep(c *rat) PS{ +func Rep(c rat) PS { Z := mkPS(); go repeat(c,Z); return Z; @@ -389,24 +383,24 @@ func Rep(c *rat) PS{ // Monomial c*x^n -func Mon(c *rat, n int) PS{ +func Mon(c rat, n int) PS { Z:=mkPS(); - go func(c *rat, n int, Z PS){ + go func() { if(c.num!=0) { for ; n>0; n=n-1 { put(zero,Z) } put(c,Z); } put(finis,Z); - }(c, n, Z); + }(); return Z; } -func Shift(c *rat, U PS) PS{ +func Shift(c rat, U PS) PS { Z := mkPS(); - go func(c *rat, U, Z PS){ + go func() { put(c,Z); copy(U,Z); - }(c, U, Z); + }(); return Z; } @@ -415,10 +409,10 @@ func Shift(c *rat, U PS) PS{ // Convert array of coefficients, constant term first // to a (finite) power series -/* BUG: NEED LEN OF ARRAY -func Poly(a [] *rat) PS{ +/* +func Poly(a []rat) PS { Z:=mkPS(); - begin func(a [] *rat, Z PS){ + begin func(a []rat, Z PS) { j:=0; done:=0; for j=len(a); !done&&j>0; j=j-1) @@ -436,9 +430,9 @@ func Poly(a [] *rat) PS{ // let V = v + x*VV // then UV = u*v + x*(u*VV+v*UU) + x*x*UU*VV -func Mul(U, V PS) PS{ +func Mul(U, V PS) PS { Z:=mkPS(); - go func(U, V, Z PS){ + go func() { <-Z.req; uv := get2(U,V); if end(uv[0])!=0 || end(uv[1]) != 0 { @@ -452,15 +446,15 @@ func Mul(U, V PS) PS{ Z.dat <- get(W); copy(Add(W,Mul(UU[1],VV[1])),Z); } - }(U, V, Z); + }(); return Z; } // Differentiate -func Diff(U PS) PS{ +func Diff(U PS) PS { Z:=mkPS(); - go func(U, Z PS){ + go func() { <-Z.req; u := get(U); if end(u) == 0 { @@ -475,14 +469,14 @@ func Diff(U PS) PS{ } } Z.dat <- finis; - }(U, Z); + }(); return Z; } // Integrate, with const of integration -func Integ(c *rat,U PS) PS{ +func Integ(c rat,U PS) PS { Z:=mkPS(); - go func(c *rat, U, Z PS){ + go func() { put(c,Z); done:=false; for i:=1; !done; i++ { @@ -492,15 +486,15 @@ func Integ(c *rat,U PS) PS{ Z.dat <- mul(i2tor(1,int64(i)),u); } Z.dat <- finis; - }(c, U, Z); + }(); return Z; } // Binomial theorem (1+x)^c -func Binom(c *rat) PS{ +func Binom(c rat) PS { Z:=mkPS(); - go func(c *rat, Z PS){ + go func() { n := 1; t := itor(1); for c.num!=0 { @@ -510,7 +504,7 @@ func Binom(c *rat) PS{ n++; } put(finis,Z); - }(c, Z); + }(); return Z; } @@ -522,16 +516,16 @@ func Binom(c *rat) PS{ // u*ZZ + z*UU +x*UU*ZZ = 0 // ZZ = -UU*(z+x*ZZ)/u; -func Recip(U PS) PS{ +func Recip(U PS) PS { Z:=mkPS(); - go func(U, Z PS){ + go func() { ZZ:=mkPS2(); <-Z.req; z := inv(get(U)); Z.dat <- z; split(Mul(Cmul(neg(z),U),Shift(z,ZZ[0])),ZZ); copy(ZZ[1],Z); - }(U, Z); + }(); return Z; } @@ -542,7 +536,7 @@ func Recip(U PS) PS{ // DZ = Z*DU // integrate to get Z -func Exp(U PS) PS{ +func Exp(U PS) PS { ZZ := mkPS2(); split(Integ(one,Mul(ZZ[0],Diff(U))),ZZ); return ZZ[1]; @@ -556,7 +550,7 @@ func Exp(U PS) PS{ func Subst(U, V PS) PS { Z:= mkPS(); - go func(U, V, Z PS) { + go func() { VV := Split(V); <-Z.req; u := get(U); @@ -565,16 +559,16 @@ func Subst(U, V PS) PS { if end(get(VV[0])) != 0 { put(finis,Z); } else { copy(Mul(VV[0],Subst(U,VV[1])),Z); } } - }(U, V, Z); + }(); return Z; } // Monomial Substition: U(c x^n) // Each Ui is multiplied by c^i and followed by n-1 zeros -func MonSubst(U PS, c0 *rat, n int) PS { +func MonSubst(U PS, c0 rat, n int) PS { Z:= mkPS(); - go func(U, Z PS, c0 *rat, n int) { + go func() { c := one; for { <-Z.req; @@ -590,7 +584,7 @@ func MonSubst(U PS, c0 *rat, n int) PS { Z.dat <- zero; } } - }(U, Z, c0, n); + }(); return Z; } @@ -606,7 +600,7 @@ func Init() { Twos = Rep(itor(2)); } -func check(U PS, c *rat, count int, str string) { +func check(U PS, c rat, count int, str string) { for i := 0; i < count; i++ { r := get(U); if !r.eq(c) { @@ -621,7 +615,7 @@ func check(U PS, c *rat, count int, str string) { } const N=10 -func checka(U PS, a []*rat, str string) { +func checka(U PS, a []rat, str string) { for i := 0; i < N; i++ { check(U, a[i], 1, str); } @@ -630,30 +624,28 @@ func checka(U PS, a []*rat, str string) { func main() { Init(); if len(sys.Args) > 1 { // print - print("Ones: "); Printn(Ones, 10); - print("Twos: "); Printn(Twos, 10); - print("Add: "); Printn(Add(Ones, Twos), 10); - print("Diff: "); Printn(Diff(Ones), 10); - print("Integ: "); Printn(Integ(zero, Ones), 10); - print("CMul: "); Printn(Cmul(neg(one), Ones), 10); - print("Sub: "); Printn(Sub(Ones, Twos), 10); - print("Mul: "); Printn(Mul(Ones, Ones), 10); - print("Exp: "); Printn(Exp(Ones), 15); - print("MonSubst: "); Printn(MonSubst(Ones, neg(one), 2), 10); - print("ATan: "); Printn(Integ(zero, MonSubst(Ones, neg(one), 2)), 10); + print("Ones: "); printn(Ones, 10); + print("Twos: "); printn(Twos, 10); + print("Add: "); printn(Add(Ones, Twos), 10); + print("Diff: "); printn(Diff(Ones), 10); + print("Integ: "); printn(Integ(zero, Ones), 10); + print("CMul: "); printn(Cmul(neg(one), Ones), 10); + print("Sub: "); printn(Sub(Ones, Twos), 10); + print("Mul: "); printn(Mul(Ones, Ones), 10); + print("Exp: "); printn(Exp(Ones), 15); + print("MonSubst: "); printn(MonSubst(Ones, neg(one), 2), 10); + print("ATan: "); printn(Integ(zero, MonSubst(Ones, neg(one), 2)), 10); } else { // test check(Ones, one, 5, "Ones"); check(Add(Ones, Ones), itor(2), 0, "Add Ones Ones"); // 1 1 1 1 1 check(Add(Ones, Twos), itor(3), 0, "Add Ones Twos"); // 3 3 3 3 3 - a := make([] *rat, N); + a := make([]rat, N); d := Diff(Ones); - // BUG: want array initializer for i:=0; i < N; i++ { a[i] = itor(int64(i+1)) } checka(d, a, "Diff"); // 1 2 3 4 5 in := Integ(zero, Ones); - // BUG: want array initializer a[0] = zero; // integration constant for i:=1; i < N; i++ { a[i] = i2tor(1, int64(i)) @@ -662,13 +654,11 @@ func main() { check(Cmul(neg(one), Twos), itor(-2), 10, "CMul"); // -1 -1 -1 -1 -1 check(Sub(Ones, Twos), itor(-1), 0, "Sub Ones Twos"); // -1 -1 -1 -1 -1 m := Mul(Ones, Ones); - // BUG: want array initializer for i:=0; i < N; i++ { a[i] = itor(int64(i+1)) } checka(m, a, "Mul"); // 1 2 3 4 5 e := Exp(Ones); - // BUG: want array initializer a[0] = itor(1); a[1] = itor(1); a[2] = i2tor(3,2); @@ -681,7 +671,6 @@ func main() { a[9] = i2tor(4596553,362880); checka(e, a, "Exp"); // 1 1 3/2 13/6 73/24 at := Integ(zero, MonSubst(Ones, neg(one), 2)); - // BUG: want array initializer for c, i := 1, 0; i < N; i++ { if i%2 == 0 { a[i] = zero @@ -693,7 +682,6 @@ func main() { checka(at, a, "ATan"); // 0 -1 0 -1/3 0 -1/5 /* t := Revert(Integ(zero, MonSubst(Ones, neg(one), 2))); - // BUG: want array initializer a[0] = zero; a[1] = itor(1); a[2] = zero; @@ -707,5 +695,4 @@ func main() { checka(t, a, "Tan"); // 0 1 0 1/3 0 2/15 */ } - sys.Exit(0); // BUG: force waiting goroutines to exit } diff --git a/test/chan/powser2.go b/test/chan/powser2.go index 17e2aa2812..6e769e98cb 100644 --- a/test/chan/powser2.go +++ b/test/chan/powser2.go @@ -11,6 +11,8 @@ // See Squinting at Power Series by Doug McIlroy, // http://www.cs.bell-labs.com/who/rsc/thread/squint.pdf // Like powser1.go but uses channels of interfaces. +// Has not been cleaned up as much as powser1.go, to keep +// it distinct and therefore a different test. package main @@ -129,8 +131,8 @@ func get(in *dch) *rat { // Get one item from each of n demand channels -func getn(in []*dch, n int) []item { - // BUG n:=len(in); +func getn(in []*dch) []item { + n:=len(in); if n != 2 { panic("bad n in getn") }; req := make([] chan int, 2); dat := make([] chan item, 2); @@ -165,7 +167,7 @@ func getn(in []*dch, n int) []item { // Get one item from each of 2 demand channels func get2(in0 *dch, in1 *dch) []item { - return getn([]*dch{in0, in1}, 2); + return getn([]*dch{in0, in1}); } func copy(in *dch, out *dch){ @@ -420,7 +422,7 @@ func Shift(c *rat, U PS) PS{ // Convert array of coefficients, constant term first // to a (finite) power series -/* BUG: NEED LEN OF ARRAY +/* func Poly(a [] *rat) PS{ Z:=mkPS(); begin func(a [] *rat, Z PS){ @@ -652,13 +654,11 @@ func main() { check(Add(Ones, Twos), itor(3), 0, "Add Ones Twos"); // 3 3 3 3 3 a := make([]*rat, N); d := Diff(Ones); - // BUG: want array initializer for i:=0; i < N; i++ { a[i] = itor(int64(i+1)) } checka(d, a, "Diff"); // 1 2 3 4 5 in := Integ(zero, Ones); - // BUG: want array initializer a[0] = zero; // integration constant for i:=1; i < N; i++ { a[i] = i2tor(1, int64(i)) @@ -667,13 +667,11 @@ func main() { check(Cmul(neg(one), Twos), itor(-2), 10, "CMul"); // -1 -1 -1 -1 -1 check(Sub(Ones, Twos), itor(-1), 0, "Sub Ones Twos"); // -1 -1 -1 -1 -1 m := Mul(Ones, Ones); - // BUG: want array initializer for i:=0; i < N; i++ { a[i] = itor(int64(i+1)) } checka(m, a, "Mul"); // 1 2 3 4 5 e := Exp(Ones); - // BUG: want array initializer a[0] = itor(1); a[1] = itor(1); a[2] = i2tor(3,2); @@ -686,7 +684,6 @@ func main() { a[9] = i2tor(4596553,362880); checka(e, a, "Exp"); // 1 1 3/2 13/6 73/24 at := Integ(zero, MonSubst(Ones, neg(one), 2)); - // BUG: want array initializer for c, i := 1, 0; i < N; i++ { if i%2 == 0 { a[i] = zero @@ -698,7 +695,6 @@ func main() { checka(at, a, "ATan"); // 0 -1 0 -1/3 0 -1/5 /* t := Revert(Integ(zero, MonSubst(Ones, neg(one), 2))); - // BUG: want array initializer a[0] = zero; a[1] = itor(1); a[2] = zero; @@ -712,5 +708,4 @@ func main() { checka(t, a, "Tan"); // 0 1 0 1/3 0 2/15 */ } - sys.Exit(0); // BUG: force waiting goroutines to exit }