--- a/src/HOL/HoareParallel/OG_Examples.thy Thu Sep 17 14:17:37 2009 +1000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,549 +0,0 @@
-
-header {* \section{Examples} *}
-
-theory OG_Examples imports OG_Syntax begin
-
-subsection {* Mutual Exclusion *}
-
-subsubsection {* Peterson's Algorithm I*}
-
-text {* Eike Best. "Semantics of Sequential and Parallel Programs", page 217. *}
-
-record Petersons_mutex_1 =
- pr1 :: nat
- pr2 :: nat
- in1 :: bool
- in2 :: bool
- hold :: nat
-
-lemma Petersons_mutex_1:
- "\<parallel>- .{\<acute>pr1=0 \<and> \<not>\<acute>in1 \<and> \<acute>pr2=0 \<and> \<not>\<acute>in2 }.
- COBEGIN .{\<acute>pr1=0 \<and> \<not>\<acute>in1}.
- WHILE True INV .{\<acute>pr1=0 \<and> \<not>\<acute>in1}.
- DO
- .{\<acute>pr1=0 \<and> \<not>\<acute>in1}. \<langle> \<acute>in1:=True,,\<acute>pr1:=1 \<rangle>;;
- .{\<acute>pr1=1 \<and> \<acute>in1}. \<langle> \<acute>hold:=1,,\<acute>pr1:=2 \<rangle>;;
- .{\<acute>pr1=2 \<and> \<acute>in1 \<and> (\<acute>hold=1 \<or> \<acute>hold=2 \<and> \<acute>pr2=2)}.
- AWAIT (\<not>\<acute>in2 \<or> \<not>(\<acute>hold=1)) THEN \<acute>pr1:=3 END;;
- .{\<acute>pr1=3 \<and> \<acute>in1 \<and> (\<acute>hold=1 \<or> \<acute>hold=2 \<and> \<acute>pr2=2)}.
- \<langle>\<acute>in1:=False,,\<acute>pr1:=0\<rangle>
- OD .{\<acute>pr1=0 \<and> \<not>\<acute>in1}.
- \<parallel>
- .{\<acute>pr2=0 \<and> \<not>\<acute>in2}.
- WHILE True INV .{\<acute>pr2=0 \<and> \<not>\<acute>in2}.
- DO
- .{\<acute>pr2=0 \<and> \<not>\<acute>in2}. \<langle> \<acute>in2:=True,,\<acute>pr2:=1 \<rangle>;;
- .{\<acute>pr2=1 \<and> \<acute>in2}. \<langle> \<acute>hold:=2,,\<acute>pr2:=2 \<rangle>;;
- .{\<acute>pr2=2 \<and> \<acute>in2 \<and> (\<acute>hold=2 \<or> (\<acute>hold=1 \<and> \<acute>pr1=2))}.
- AWAIT (\<not>\<acute>in1 \<or> \<not>(\<acute>hold=2)) THEN \<acute>pr2:=3 END;;
- .{\<acute>pr2=3 \<and> \<acute>in2 \<and> (\<acute>hold=2 \<or> (\<acute>hold=1 \<and> \<acute>pr1=2))}.
- \<langle>\<acute>in2:=False,,\<acute>pr2:=0\<rangle>
- OD .{\<acute>pr2=0 \<and> \<not>\<acute>in2}.
- COEND
- .{\<acute>pr1=0 \<and> \<not>\<acute>in1 \<and> \<acute>pr2=0 \<and> \<not>\<acute>in2}."
-apply oghoare
---{* 104 verification conditions. *}
-apply auto
-done
-
-subsubsection {*Peterson's Algorithm II: A Busy Wait Solution *}
-
-text {* Apt and Olderog. "Verification of sequential and concurrent Programs", page 282. *}
-
-record Busy_wait_mutex =
- flag1 :: bool
- flag2 :: bool
- turn :: nat
- after1 :: bool
- after2 :: bool
-
-lemma Busy_wait_mutex:
- "\<parallel>- .{True}.
- \<acute>flag1:=False,, \<acute>flag2:=False,,
- COBEGIN .{\<not>\<acute>flag1}.
- WHILE True
- INV .{\<not>\<acute>flag1}.
- DO .{\<not>\<acute>flag1}. \<langle> \<acute>flag1:=True,,\<acute>after1:=False \<rangle>;;
- .{\<acute>flag1 \<and> \<not>\<acute>after1}. \<langle> \<acute>turn:=1,,\<acute>after1:=True \<rangle>;;
- .{\<acute>flag1 \<and> \<acute>after1 \<and> (\<acute>turn=1 \<or> \<acute>turn=2)}.
- WHILE \<not>(\<acute>flag2 \<longrightarrow> \<acute>turn=2)
- INV .{\<acute>flag1 \<and> \<acute>after1 \<and> (\<acute>turn=1 \<or> \<acute>turn=2)}.
- DO .{\<acute>flag1 \<and> \<acute>after1 \<and> (\<acute>turn=1 \<or> \<acute>turn=2)}. SKIP OD;;
- .{\<acute>flag1 \<and> \<acute>after1 \<and> (\<acute>flag2 \<and> \<acute>after2 \<longrightarrow> \<acute>turn=2)}.
- \<acute>flag1:=False
- OD
- .{False}.
- \<parallel>
- .{\<not>\<acute>flag2}.
- WHILE True
- INV .{\<not>\<acute>flag2}.
- DO .{\<not>\<acute>flag2}. \<langle> \<acute>flag2:=True,,\<acute>after2:=False \<rangle>;;
- .{\<acute>flag2 \<and> \<not>\<acute>after2}. \<langle> \<acute>turn:=2,,\<acute>after2:=True \<rangle>;;
- .{\<acute>flag2 \<and> \<acute>after2 \<and> (\<acute>turn=1 \<or> \<acute>turn=2)}.
- WHILE \<not>(\<acute>flag1 \<longrightarrow> \<acute>turn=1)
- INV .{\<acute>flag2 \<and> \<acute>after2 \<and> (\<acute>turn=1 \<or> \<acute>turn=2)}.
- DO .{\<acute>flag2 \<and> \<acute>after2 \<and> (\<acute>turn=1 \<or> \<acute>turn=2)}. SKIP OD;;
- .{\<acute>flag2 \<and> \<acute>after2 \<and> (\<acute>flag1 \<and> \<acute>after1 \<longrightarrow> \<acute>turn=1)}.
- \<acute>flag2:=False
- OD
- .{False}.
- COEND
- .{False}."
-apply oghoare
---{* 122 vc *}
-apply auto
-done
-
-subsubsection {* Peterson's Algorithm III: A Solution using Semaphores *}
-
-record Semaphores_mutex =
- out :: bool
- who :: nat
-
-lemma Semaphores_mutex:
- "\<parallel>- .{i\<noteq>j}.
- \<acute>out:=True ,,
- COBEGIN .{i\<noteq>j}.
- WHILE True INV .{i\<noteq>j}.
- DO .{i\<noteq>j}. AWAIT \<acute>out THEN \<acute>out:=False,, \<acute>who:=i END;;
- .{\<not>\<acute>out \<and> \<acute>who=i \<and> i\<noteq>j}. \<acute>out:=True OD
- .{False}.
- \<parallel>
- .{i\<noteq>j}.
- WHILE True INV .{i\<noteq>j}.
- DO .{i\<noteq>j}. AWAIT \<acute>out THEN \<acute>out:=False,,\<acute>who:=j END;;
- .{\<not>\<acute>out \<and> \<acute>who=j \<and> i\<noteq>j}. \<acute>out:=True OD
- .{False}.
- COEND
- .{False}."
-apply oghoare
---{* 38 vc *}
-apply auto
-done
-
-subsubsection {* Peterson's Algorithm III: Parameterized version: *}
-
-lemma Semaphores_parameterized_mutex:
- "0<n \<Longrightarrow> \<parallel>- .{True}.
- \<acute>out:=True ,,
- COBEGIN
- SCHEME [0\<le> i< n]
- .{True}.
- WHILE True INV .{True}.
- DO .{True}. AWAIT \<acute>out THEN \<acute>out:=False,, \<acute>who:=i END;;
- .{\<not>\<acute>out \<and> \<acute>who=i}. \<acute>out:=True OD
- .{False}.
- COEND
- .{False}."
-apply oghoare
---{* 20 vc *}
-apply auto
-done
-
-subsubsection{* The Ticket Algorithm *}
-
-record Ticket_mutex =
- num :: nat
- nextv :: nat
- turn :: "nat list"
- index :: nat
-
-lemma Ticket_mutex:
- "\<lbrakk> 0<n; I=\<guillemotleft>n=length \<acute>turn \<and> 0<\<acute>nextv \<and> (\<forall>k l. k<n \<and> l<n \<and> k\<noteq>l
- \<longrightarrow> \<acute>turn!k < \<acute>num \<and> (\<acute>turn!k =0 \<or> \<acute>turn!k\<noteq>\<acute>turn!l))\<guillemotright> \<rbrakk>
- \<Longrightarrow> \<parallel>- .{n=length \<acute>turn}.
- \<acute>index:= 0,,
- WHILE \<acute>index < n INV .{n=length \<acute>turn \<and> (\<forall>i<\<acute>index. \<acute>turn!i=0)}.
- DO \<acute>turn:= \<acute>turn[\<acute>index:=0],, \<acute>index:=\<acute>index +1 OD,,
- \<acute>num:=1 ,, \<acute>nextv:=1 ,,
- COBEGIN
- SCHEME [0\<le> i< n]
- .{\<acute>I}.
- WHILE True INV .{\<acute>I}.
- DO .{\<acute>I}. \<langle> \<acute>turn :=\<acute>turn[i:=\<acute>num],, \<acute>num:=\<acute>num+1 \<rangle>;;
- .{\<acute>I}. WAIT \<acute>turn!i=\<acute>nextv END;;
- .{\<acute>I \<and> \<acute>turn!i=\<acute>nextv}. \<acute>nextv:=\<acute>nextv+1
- OD
- .{False}.
- COEND
- .{False}."
-apply oghoare
---{* 35 vc *}
-apply simp_all
---{* 21 vc *}
-apply(tactic {* ALLGOALS (clarify_tac @{claset}) *})
---{* 11 vc *}
-apply simp_all
-apply(tactic {* ALLGOALS (clarify_tac @{claset}) *})
---{* 10 subgoals left *}
-apply(erule less_SucE)
- apply simp
-apply simp
---{* 9 subgoals left *}
-apply(case_tac "i=k")
- apply force
-apply simp
-apply(case_tac "i=l")
- apply force
-apply force
---{* 8 subgoals left *}
-prefer 8
-apply force
-apply force
---{* 6 subgoals left *}
-prefer 6
-apply(erule_tac x=i in allE)
-apply fastsimp
---{* 5 subgoals left *}
-prefer 5
-apply(case_tac [!] "j=k")
---{* 10 subgoals left *}
-apply simp_all
-apply(erule_tac x=k in allE)
-apply force
---{* 9 subgoals left *}
-apply(case_tac "j=l")
- apply simp
- apply(erule_tac x=k in allE)
- apply(erule_tac x=k in allE)
- apply(erule_tac x=l in allE)
- apply force
-apply(erule_tac x=k in allE)
-apply(erule_tac x=k in allE)
-apply(erule_tac x=l in allE)
-apply force
---{* 8 subgoals left *}
-apply force
-apply(case_tac "j=l")
- apply simp
-apply(erule_tac x=k in allE)
-apply(erule_tac x=l in allE)
-apply force
-apply force
-apply force
---{* 5 subgoals left *}
-apply(erule_tac x=k in allE)
-apply(erule_tac x=l in allE)
-apply(case_tac "j=l")
- apply force
-apply force
-apply force
---{* 3 subgoals left *}
-apply(erule_tac x=k in allE)
-apply(erule_tac x=l in allE)
-apply(case_tac "j=l")
- apply force
-apply force
-apply force
---{* 1 subgoals left *}
-apply(erule_tac x=k in allE)
-apply(erule_tac x=l in allE)
-apply(case_tac "j=l")
- apply force
-apply force
-done
-
-subsection{* Parallel Zero Search *}
-
-text {* Synchronized Zero Search. Zero-6 *}
-
-text {*Apt and Olderog. "Verification of sequential and concurrent Programs" page 294: *}
-
-record Zero_search =
- turn :: nat
- found :: bool
- x :: nat
- y :: nat
-
-lemma Zero_search:
- "\<lbrakk>I1= \<guillemotleft> a\<le>\<acute>x \<and> (\<acute>found \<longrightarrow> (a<\<acute>x \<and> f(\<acute>x)=0) \<or> (\<acute>y\<le>a \<and> f(\<acute>y)=0))
- \<and> (\<not>\<acute>found \<and> a<\<acute> x \<longrightarrow> f(\<acute>x)\<noteq>0) \<guillemotright> ;
- I2= \<guillemotleft>\<acute>y\<le>a+1 \<and> (\<acute>found \<longrightarrow> (a<\<acute>x \<and> f(\<acute>x)=0) \<or> (\<acute>y\<le>a \<and> f(\<acute>y)=0))
- \<and> (\<not>\<acute>found \<and> \<acute>y\<le>a \<longrightarrow> f(\<acute>y)\<noteq>0) \<guillemotright> \<rbrakk> \<Longrightarrow>
- \<parallel>- .{\<exists> u. f(u)=0}.
- \<acute>turn:=1,, \<acute>found:= False,,
- \<acute>x:=a,, \<acute>y:=a+1 ,,
- COBEGIN .{\<acute>I1}.
- WHILE \<not>\<acute>found
- INV .{\<acute>I1}.
- DO .{a\<le>\<acute>x \<and> (\<acute>found \<longrightarrow> \<acute>y\<le>a \<and> f(\<acute>y)=0) \<and> (a<\<acute>x \<longrightarrow> f(\<acute>x)\<noteq>0)}.
- WAIT \<acute>turn=1 END;;
- .{a\<le>\<acute>x \<and> (\<acute>found \<longrightarrow> \<acute>y\<le>a \<and> f(\<acute>y)=0) \<and> (a<\<acute>x \<longrightarrow> f(\<acute>x)\<noteq>0)}.
- \<acute>turn:=2;;
- .{a\<le>\<acute>x \<and> (\<acute>found \<longrightarrow> \<acute>y\<le>a \<and> f(\<acute>y)=0) \<and> (a<\<acute>x \<longrightarrow> f(\<acute>x)\<noteq>0)}.
- \<langle> \<acute>x:=\<acute>x+1,,
- IF f(\<acute>x)=0 THEN \<acute>found:=True ELSE SKIP FI\<rangle>
- OD;;
- .{\<acute>I1 \<and> \<acute>found}.
- \<acute>turn:=2
- .{\<acute>I1 \<and> \<acute>found}.
- \<parallel>
- .{\<acute>I2}.
- WHILE \<not>\<acute>found
- INV .{\<acute>I2}.
- DO .{\<acute>y\<le>a+1 \<and> (\<acute>found \<longrightarrow> a<\<acute>x \<and> f(\<acute>x)=0) \<and> (\<acute>y\<le>a \<longrightarrow> f(\<acute>y)\<noteq>0)}.
- WAIT \<acute>turn=2 END;;
- .{\<acute>y\<le>a+1 \<and> (\<acute>found \<longrightarrow> a<\<acute>x \<and> f(\<acute>x)=0) \<and> (\<acute>y\<le>a \<longrightarrow> f(\<acute>y)\<noteq>0)}.
- \<acute>turn:=1;;
- .{\<acute>y\<le>a+1 \<and> (\<acute>found \<longrightarrow> a<\<acute>x \<and> f(\<acute>x)=0) \<and> (\<acute>y\<le>a \<longrightarrow> f(\<acute>y)\<noteq>0)}.
- \<langle> \<acute>y:=(\<acute>y - 1),,
- IF f(\<acute>y)=0 THEN \<acute>found:=True ELSE SKIP FI\<rangle>
- OD;;
- .{\<acute>I2 \<and> \<acute>found}.
- \<acute>turn:=1
- .{\<acute>I2 \<and> \<acute>found}.
- COEND
- .{f(\<acute>x)=0 \<or> f(\<acute>y)=0}."
-apply oghoare
---{* 98 verification conditions *}
-apply auto
---{* auto takes about 3 minutes !! *}
-done
-
-text {* Easier Version: without AWAIT. Apt and Olderog. page 256: *}
-
-lemma Zero_Search_2:
-"\<lbrakk>I1=\<guillemotleft> a\<le>\<acute>x \<and> (\<acute>found \<longrightarrow> (a<\<acute>x \<and> f(\<acute>x)=0) \<or> (\<acute>y\<le>a \<and> f(\<acute>y)=0))
- \<and> (\<not>\<acute>found \<and> a<\<acute>x \<longrightarrow> f(\<acute>x)\<noteq>0)\<guillemotright>;
- I2= \<guillemotleft>\<acute>y\<le>a+1 \<and> (\<acute>found \<longrightarrow> (a<\<acute>x \<and> f(\<acute>x)=0) \<or> (\<acute>y\<le>a \<and> f(\<acute>y)=0))
- \<and> (\<not>\<acute>found \<and> \<acute>y\<le>a \<longrightarrow> f(\<acute>y)\<noteq>0)\<guillemotright>\<rbrakk> \<Longrightarrow>
- \<parallel>- .{\<exists>u. f(u)=0}.
- \<acute>found:= False,,
- \<acute>x:=a,, \<acute>y:=a+1,,
- COBEGIN .{\<acute>I1}.
- WHILE \<not>\<acute>found
- INV .{\<acute>I1}.
- DO .{a\<le>\<acute>x \<and> (\<acute>found \<longrightarrow> \<acute>y\<le>a \<and> f(\<acute>y)=0) \<and> (a<\<acute>x \<longrightarrow> f(\<acute>x)\<noteq>0)}.
- \<langle> \<acute>x:=\<acute>x+1,,IF f(\<acute>x)=0 THEN \<acute>found:=True ELSE SKIP FI\<rangle>
- OD
- .{\<acute>I1 \<and> \<acute>found}.
- \<parallel>
- .{\<acute>I2}.
- WHILE \<not>\<acute>found
- INV .{\<acute>I2}.
- DO .{\<acute>y\<le>a+1 \<and> (\<acute>found \<longrightarrow> a<\<acute>x \<and> f(\<acute>x)=0) \<and> (\<acute>y\<le>a \<longrightarrow> f(\<acute>y)\<noteq>0)}.
- \<langle> \<acute>y:=(\<acute>y - 1),,IF f(\<acute>y)=0 THEN \<acute>found:=True ELSE SKIP FI\<rangle>
- OD
- .{\<acute>I2 \<and> \<acute>found}.
- COEND
- .{f(\<acute>x)=0 \<or> f(\<acute>y)=0}."
-apply oghoare
---{* 20 vc *}
-apply auto
---{* auto takes aprox. 2 minutes. *}
-done
-
-subsection {* Producer/Consumer *}
-
-subsubsection {* Previous lemmas *}
-
-lemma nat_lemma2: "\<lbrakk> b = m*(n::nat) + t; a = s*n + u; t=u; b-a < n \<rbrakk> \<Longrightarrow> m \<le> s"
-proof -
- assume "b = m*(n::nat) + t" "a = s*n + u" "t=u"
- hence "(m - s) * n = b - a" by (simp add: diff_mult_distrib)
- also assume "\<dots> < n"
- finally have "m - s < 1" by simp
- thus ?thesis by arith
-qed
-
-lemma mod_lemma: "\<lbrakk> (c::nat) \<le> a; a < b; b - c < n \<rbrakk> \<Longrightarrow> b mod n \<noteq> a mod n"
-apply(subgoal_tac "b=b div n*n + b mod n" )
- prefer 2 apply (simp add: mod_div_equality [symmetric])
-apply(subgoal_tac "a=a div n*n + a mod n")
- prefer 2
- apply(simp add: mod_div_equality [symmetric])
-apply(subgoal_tac "b - a \<le> b - c")
- prefer 2 apply arith
-apply(drule le_less_trans)
-back
- apply assumption
-apply(frule less_not_refl2)
-apply(drule less_imp_le)
-apply (drule_tac m = "a" and k = n in div_le_mono)
-apply(safe)
-apply(frule_tac b = "b" and a = "a" and n = "n" in nat_lemma2, assumption, assumption)
-apply assumption
-apply(drule order_antisym, assumption)
-apply(rotate_tac -3)
-apply(simp)
-done
-
-
-subsubsection {* Producer/Consumer Algorithm *}
-
-record Producer_consumer =
- ins :: nat
- outs :: nat
- li :: nat
- lj :: nat
- vx :: nat
- vy :: nat
- buffer :: "nat list"
- b :: "nat list"
-
-text {* The whole proof takes aprox. 4 minutes. *}
-
-lemma Producer_consumer:
- "\<lbrakk>INIT= \<guillemotleft>0<length a \<and> 0<length \<acute>buffer \<and> length \<acute>b=length a\<guillemotright> ;
- I= \<guillemotleft>(\<forall>k<\<acute>ins. \<acute>outs\<le>k \<longrightarrow> (a ! k) = \<acute>buffer ! (k mod (length \<acute>buffer))) \<and>
- \<acute>outs\<le>\<acute>ins \<and> \<acute>ins-\<acute>outs\<le>length \<acute>buffer\<guillemotright> ;
- I1= \<guillemotleft>\<acute>I \<and> \<acute>li\<le>length a\<guillemotright> ;
- p1= \<guillemotleft>\<acute>I1 \<and> \<acute>li=\<acute>ins\<guillemotright> ;
- I2 = \<guillemotleft>\<acute>I \<and> (\<forall>k<\<acute>lj. (a ! k)=(\<acute>b ! k)) \<and> \<acute>lj\<le>length a\<guillemotright> ;
- p2 = \<guillemotleft>\<acute>I2 \<and> \<acute>lj=\<acute>outs\<guillemotright> \<rbrakk> \<Longrightarrow>
- \<parallel>- .{\<acute>INIT}.
- \<acute>ins:=0,, \<acute>outs:=0,, \<acute>li:=0,, \<acute>lj:=0,,
- COBEGIN .{\<acute>p1 \<and> \<acute>INIT}.
- WHILE \<acute>li <length a
- INV .{\<acute>p1 \<and> \<acute>INIT}.
- DO .{\<acute>p1 \<and> \<acute>INIT \<and> \<acute>li<length a}.
- \<acute>vx:= (a ! \<acute>li);;
- .{\<acute>p1 \<and> \<acute>INIT \<and> \<acute>li<length a \<and> \<acute>vx=(a ! \<acute>li)}.
- WAIT \<acute>ins-\<acute>outs < length \<acute>buffer END;;
- .{\<acute>p1 \<and> \<acute>INIT \<and> \<acute>li<length a \<and> \<acute>vx=(a ! \<acute>li)
- \<and> \<acute>ins-\<acute>outs < length \<acute>buffer}.
- \<acute>buffer:=(list_update \<acute>buffer (\<acute>ins mod (length \<acute>buffer)) \<acute>vx);;
- .{\<acute>p1 \<and> \<acute>INIT \<and> \<acute>li<length a
- \<and> (a ! \<acute>li)=(\<acute>buffer ! (\<acute>ins mod (length \<acute>buffer)))
- \<and> \<acute>ins-\<acute>outs <length \<acute>buffer}.
- \<acute>ins:=\<acute>ins+1;;
- .{\<acute>I1 \<and> \<acute>INIT \<and> (\<acute>li+1)=\<acute>ins \<and> \<acute>li<length a}.
- \<acute>li:=\<acute>li+1
- OD
- .{\<acute>p1 \<and> \<acute>INIT \<and> \<acute>li=length a}.
- \<parallel>
- .{\<acute>p2 \<and> \<acute>INIT}.
- WHILE \<acute>lj < length a
- INV .{\<acute>p2 \<and> \<acute>INIT}.
- DO .{\<acute>p2 \<and> \<acute>lj<length a \<and> \<acute>INIT}.
- WAIT \<acute>outs<\<acute>ins END;;
- .{\<acute>p2 \<and> \<acute>lj<length a \<and> \<acute>outs<\<acute>ins \<and> \<acute>INIT}.
- \<acute>vy:=(\<acute>buffer ! (\<acute>outs mod (length \<acute>buffer)));;
- .{\<acute>p2 \<and> \<acute>lj<length a \<and> \<acute>outs<\<acute>ins \<and> \<acute>vy=(a ! \<acute>lj) \<and> \<acute>INIT}.
- \<acute>outs:=\<acute>outs+1;;
- .{\<acute>I2 \<and> (\<acute>lj+1)=\<acute>outs \<and> \<acute>lj<length a \<and> \<acute>vy=(a ! \<acute>lj) \<and> \<acute>INIT}.
- \<acute>b:=(list_update \<acute>b \<acute>lj \<acute>vy);;
- .{\<acute>I2 \<and> (\<acute>lj+1)=\<acute>outs \<and> \<acute>lj<length a \<and> (a ! \<acute>lj)=(\<acute>b ! \<acute>lj) \<and> \<acute>INIT}.
- \<acute>lj:=\<acute>lj+1
- OD
- .{\<acute>p2 \<and> \<acute>lj=length a \<and> \<acute>INIT}.
- COEND
- .{ \<forall>k<length a. (a ! k)=(\<acute>b ! k)}."
-apply oghoare
---{* 138 vc *}
-apply(tactic {* ALLGOALS (clarify_tac @{claset}) *})
---{* 112 subgoals left *}
-apply(simp_all (no_asm))
-apply(tactic {*ALLGOALS (conjI_Tac (K all_tac)) *})
---{* 930 subgoals left *}
-apply(tactic {* ALLGOALS (clarify_tac @{claset}) *})
-apply(simp_all (asm_lr) only:length_0_conv [THEN sym])
---{* 44 subgoals left *}
-apply (simp_all (asm_lr) del:length_0_conv add: neq0_conv nth_list_update mod_less_divisor mod_lemma)
---{* 32 subgoals left *}
-apply(tactic {* ALLGOALS (clarify_tac @{claset}) *})
-
-apply(tactic {* TRYALL (Lin_Arith.tac @{context}) *})
---{* 9 subgoals left *}
-apply (force simp add:less_Suc_eq)
-apply(drule sym)
-apply (force simp add:less_Suc_eq)+
-done
-
-subsection {* Parameterized Examples *}
-
-subsubsection {* Set Elements of an Array to Zero *}
-
-record Example1 =
- a :: "nat \<Rightarrow> nat"
-
-lemma Example1:
- "\<parallel>- .{True}.
- COBEGIN SCHEME [0\<le>i<n] .{True}. \<acute>a:=\<acute>a (i:=0) .{\<acute>a i=0}. COEND
- .{\<forall>i < n. \<acute>a i = 0}."
-apply oghoare
-apply simp_all
-done
-
-text {* Same example with lists as auxiliary variables. *}
-record Example1_list =
- A :: "nat list"
-lemma Example1_list:
- "\<parallel>- .{n < length \<acute>A}.
- COBEGIN
- SCHEME [0\<le>i<n] .{n < length \<acute>A}. \<acute>A:=\<acute>A[i:=0] .{\<acute>A!i=0}.
- COEND
- .{\<forall>i < n. \<acute>A!i = 0}."
-apply oghoare
-apply force+
-done
-
-subsubsection {* Increment a Variable in Parallel *}
-
-text {* First some lemmas about summation properties. *}
-(*
-lemma Example2_lemma1: "!!b. j<n \<Longrightarrow> (\<Sum>i::nat<n. b i) = (0::nat) \<Longrightarrow> b j = 0 "
-apply(induct n)
- apply simp_all
-apply(force simp add: less_Suc_eq)
-done
-*)
-lemma Example2_lemma2_aux: "!!b. j<n \<Longrightarrow>
- (\<Sum>i=0..<n. (b i::nat)) =
- (\<Sum>i=0..<j. b i) + b j + (\<Sum>i=0..<n-(Suc j) . b (Suc j + i))"
-apply(induct n)
- apply simp_all
-apply(simp add:less_Suc_eq)
- apply(auto)
-apply(subgoal_tac "n - j = Suc(n- Suc j)")
- apply simp
-apply arith
-done
-
-lemma Example2_lemma2_aux2:
- "!!b. j\<le> s \<Longrightarrow> (\<Sum>i::nat=0..<j. (b (s:=t)) i) = (\<Sum>i=0..<j. b i)"
-apply(induct j)
- apply simp_all
-done
-
-lemma Example2_lemma2:
- "!!b. \<lbrakk>j<n; b j=0\<rbrakk> \<Longrightarrow> Suc (\<Sum>i::nat=0..<n. b i)=(\<Sum>i=0..<n. (b (j := Suc 0)) i)"
-apply(frule_tac b="(b (j:=(Suc 0)))" in Example2_lemma2_aux)
-apply(erule_tac t="setsum (b(j := (Suc 0))) {0..<n}" in ssubst)
-apply(frule_tac b=b in Example2_lemma2_aux)
-apply(erule_tac t="setsum b {0..<n}" in ssubst)
-apply(subgoal_tac "Suc (setsum b {0..<j} + b j + (\<Sum>i=0..<n - Suc j. b (Suc j + i)))=(setsum b {0..<j} + Suc (b j) + (\<Sum>i=0..<n - Suc j. b (Suc j + i)))")
-apply(rotate_tac -1)
-apply(erule ssubst)
-apply(subgoal_tac "j\<le>j")
- apply(drule_tac b="b" and t="(Suc 0)" in Example2_lemma2_aux2)
-apply(rotate_tac -1)
-apply(erule ssubst)
-apply simp_all
-done
-
-
-record Example2 =
- c :: "nat \<Rightarrow> nat"
- x :: nat
-
-lemma Example_2: "0<n \<Longrightarrow>
- \<parallel>- .{\<acute>x=0 \<and> (\<Sum>i=0..<n. \<acute>c i)=0}.
- COBEGIN
- SCHEME [0\<le>i<n]
- .{\<acute>x=(\<Sum>i=0..<n. \<acute>c i) \<and> \<acute>c i=0}.
- \<langle> \<acute>x:=\<acute>x+(Suc 0),, \<acute>c:=\<acute>c (i:=(Suc 0)) \<rangle>
- .{\<acute>x=(\<Sum>i=0..<n. \<acute>c i) \<and> \<acute>c i=(Suc 0)}.
- COEND
- .{\<acute>x=n}."
-apply oghoare
-apply (simp_all cong del: strong_setsum_cong)
-apply (tactic {* ALLGOALS (clarify_tac @{claset}) *})
-apply (simp_all cong del: strong_setsum_cong)
- apply(erule (1) Example2_lemma2)
- apply(erule (1) Example2_lemma2)
- apply(erule (1) Example2_lemma2)
-apply(simp)
-done
-
-end