{VERSION 5 0 "IBM INTEL LINUX" "5.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 1 }{CSTYLE "2D Output" 2 20 "" 0 1 0 0 255 1 0 0 0 0 0 0 0 0 0 1 } {PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "Heading 1" 0 3 1 {CSTYLE "" -1 -1 "" 1 18 0 0 0 0 0 1 0 0 0 0 0 0 0 0 }1 0 0 0 8 4 0 0 0 0 0 0 -1 0 }{PSTYLE "Maple Output" 0 11 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 }3 3 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE " " 11 12 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 }1 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 0 "" 0 "" {TEXT -1 36 "L-9 MCS 563 Monday 13 Sept ember 2004" }}}{EXCHG {PARA 3 "" 0 "" {TEXT -1 51 "Symbolic-Numeric Co mputations using Newton's method" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 81 "In this worksheet we illustrate the use of Newton's method to cons truct formulas." }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "restart;" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 44 "We co nsider a very simple polynomial system:" }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 44 "p := [x[1]*x[2] - 1, x[1]^2 + t*x[2 ]^2 - 1];" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"pG7$,&*&&%\"xG6#\"\" \"F+&F)6#\"\"#F+F+F+!\"\",(*$)F(F.F+F+*&%\"tGF+)F,F.F+F+F+F/" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 23 "with Jacobian matrix J:" } {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 42 "J := Ma trix(2,2,(i,j) -> diff(p[i],x[j]));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6 #>%\"JG-%'RTABLEG6$\"*G@bO\"-%'MATRIXG6#7$7$&%\"xG6#\"\"#&F/6#\"\"\"7$ ,$F2F1,$*&%\"tGF4F.F4F1" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 60 "We nee d to evaluate both the system and its Jacobian matrix:" }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 26 "f := unapply(p,x[1], x[2]);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"fGf*6$%$x_1G%$x_2G6\"6$% )operatorG%&arrowGF)7$,&*&9$\"\"\"9%F1F1F1!\"\",(*$)F0\"\"#F1F1*&%\"tG F1)F2F7F1F1F1F3F)F)F)" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 "Jf := (a,b) -> subs(x[1]=a,x[2]=b,J);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6 #>%#JfGf*6$%\"aG%\"bG6\"6$%)operatorG%&arrowGF)-%%subsG6%/&%\"xG6#\"\" \"9$/&F26#\"\"#9%%\"JGF)F)F)" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 86 "T he following calculations show that for t = 0, the point (1,1) is a re gular solution." }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "f(1,1);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#7$\"\"!%\"t G" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "Jf(1,1);" }}{PARA 11 " " 1 "" {XPPMATH 20 "6#-%'RTABLEG6$\"*+2wP\"-%'MATRIXG6#7$7$\"\"\"F,7$ \"\"#,$%\"tGF." }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 216 "Our symbolic N ewton method takes on input two procedures f and Jf which respectively evaluate the system and its Jacobian matrix at the third argument, wh ich is a list. This list X can consist of numbers or symbols." } {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 50 "Newton \+ := proc(f::procedure,Jf::procedure,X::list)" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 50 " description `performs one symbolic Newton step`:" } }{PARA 0 "> " 0 "" {MPLTEXT 1 0 23 " local A,b,dx,sys,sol:" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 17 " b := -f(op(X));" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 17 " A := Jf(op(X));" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 22 " dx := [dx[1],dx[2]]:" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 58 " sys := LinearAlgebra[GenerateEquations](A,dx,Vector(b));" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 35 " sol := solve(\{op(sys)\},\{op(dx)\});" }} {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 " assign(sol);" }}{PARA 0 "> " 0 " " {MPLTEXT 1 0 33 " return [X[1]+dx[1],X[2]+dx[2]];" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "end proc;" }}{PARA 12 "" 1 "" {XPPMATH 20 "6#>%'N ewtonGf*6%'%\"fG%*procedureG'%#JfGF)'%\"XG%%listG6'%\"AG%\"bG%#dxG%$sy sG%$solG6\"F5C)>8%,$-9$6#-%#opG6#9&!\"\">8$-9%F<>8&7$&FG6#\"\"\"&FG6# \"\"#>8'-&%.LinearAlgebraG6#%2GenerateEquationsG6%FCFG-%'VectorG6#F8>8 (-%&solveG6$<#-F>6#FP<#-F>6#FG-%'assignG6#FenO7$,&&F@FJFKFIFK,&&F@FMFK FLFK6#%Bperforms~one~symbolic~Newton~stepGF5F5" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 26 "psA := Newton(f,Jf,[1,1]);" }}{PARA 11 "" 1 " " {XPPMATH 20 "6#>%$psAG7$,&\"\"\"F'*(#F'\"\"#F'%\"tGF',&!\"\"F'F+F'F- F',&F'F'*&#F'F*F'*&F+F'F,F-F'F-" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 176 "Note that instead of [1,1], we can only fill in [a,b]. However, \+ using [a,b] starts to get too expensive after a while, so we stick wit h [1,1], which is the solution for t = 0." }{MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "collect(psA[1],t);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#,&\"\"\"F$*(#F$\"\"#F$%\"tGF$,&!\"\"F$F(F$F* F$" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 85 "We develop the expression f ound for the first coordinate x[1] as series around t = 0:" }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "sA := series(psA [1],t=0,9);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#sAG+7%\"tG\"\"\"\"\" !#!\"\"\"\"#F'F)F+F)\"\"$F)\"\"%F)\"\"&F)\"\"'F)\"\"(F)\"\")-%\"OG6#F' \"\"*" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 80 "and we continue with thr ee more Newton steps, observe the quadratic convergence:" }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "psB := Newton(f,Jf ,psA):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "sB := series(psB[ 1],t=0,9);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#sBG+7%\"tG\"\"\"\"\"! #!\"\"\"\"#F'#!\"&\"\")F+#!#@\"#;\"\"$#!$2\"\"#K\"\"%#!$$f\"#k\"\"&#!% &R$\"$G\"\"\"'#!&l'>\"$c#\"\"(#!'rV6\"$7&F.-%\"OG6#F'\"\"*" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "psC := Newton(f,Jf,psB):" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "sC := series(psC[1],t=0,9); " }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#sCG+7%\"tG\"\"\"\"\"!#!\"\"\"\" #F'#!\"&\"\")F+#!#@\"#;\"\"$#!$H%\"$G\"\"\"%#!%JC\"$c#\"\"&#!&$RH\"%C5 \"\"'#!'Dd=\"%[?\"\"(#!(6PU#\"%#>)F.-%\"OG6#F'\"\"*" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "psD := Newton(f,Jf,psC):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "sD := series(psD[1],t=0,9);" }} {PARA 11 "" 1 "" {XPPMATH 20 "6#>%#sDG+7%\"tG\"\"\"\"\"!#!\"\"\"\"#F'# !\"&\"\")F+#!#@\"#;\"\"$#!$H%\"$G\"\"\"%#!%JC\"$c#\"\"&#!&$RH\"%C5\"\" '#!'Dd=\"%[?\"\"(#!(X[p*\"&oF$F.-%\"OG6#F'\"\"*" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 24 "psE := Newton(f,Jf,psD):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "sE := series(psE[1],t=0,9);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#sEG+7%\"tG\"\"\"\"\"!#!\"\"\"\"#F'#!\"&\"\")F+#!# @\"#;\"\"$#!$H%\"$G\"\"\"%#!%JC\"$c#\"\"&#!&$RH\"%C5\"\"'#!'Dd=\"%[?\" \"(#!(X[p*\"&oF$F.-%\"OG6#F'\"\"*" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 67 "The following calculations make the conversions even more explicit :" }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "pD \+ := convert(sD,polynom): " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 26 "pA := convert(sA,polynom):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 26 "pB := convert(sB,polynom):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 26 "pC := convert(sC,polynom):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "pA-pD;" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#,0*$)%\"tG\" \"#\"\"\"#F(\"\")*&#\"#8\"#;F()F&\"\"$F(F(*&#\"$l$\"$G\"F()F&\"\"%F(F( *&#\"%.B\"$c#F()F&\"\"&F(F(*&#\"&\"))G\"%C5F()F&\"\"'F(F(*&#\"',Z=\"%[ ?F()F&\"\"(F(F(*&#\"(h%y'*\"&oF$F()F&F*F(F(" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "pB-pD;" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#,,*$)%\"t G\"\"%\"\"\"#F(\"$G\"*&#\"#f\"$c#F()F&\"\"&F(F(*&#\"%LA\"%C5F()F&\"\"' F(F(*&#\"&0%G\"%[?F()F&\"\"(F(F(*&#\"(,^P#\"&oF$F()F&\"\")F(F(" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "pC-pD;" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#,$*$)%\"tG\"\")\"\"\"#F(\"&oF$" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 138 "After one Newton iteration, the error is O(t^2), then the error becomes O(t^4), and after the third Newton iteration, the e rror is O(t^8)." }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 128 "Similar to the quadratic convergence of Newton's method as we \+ know it, we can construct more and more accurate series solutions." } {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 205 "Notice howev er, that the solutions we obtained are purely formal. The difference \+ between the result of the first and fourth Newton iteration when evalu ate at a small value for t is not really significant:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "fA := unapply(pA,t);" }}{PARA 11 " " 1 "" {XPPMATH 20 "6#>%#fAGf*6#%\"tG6\"6$%)operatorG%&arrowGF(,4\"\" \"F-*&#F-\"\"#F-9$F-!\"\"*&#F-F0F-*$)F1F0F-F-F2*&#F-F0F-*$)F1\"\"$F-F- F2*&#F-F0F-*$)F1\"\"%F-F-F2*&#F-F0F-*$)F1\"\"&F-F-F2*&#F-F0F-*$)F1\"\" 'F-F-F2*&#F-F0F-*$)F1\"\"(F-F-F2*&#F-F0F-*$)F1\"\")F-F-F2F(F(F(" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "fD := unapply(pD,t);" }} {PARA 11 "" 1 "" {XPPMATH 20 "6#>%#fDGf*6#%\"tG6\"6$%)operatorG%&arrow GF(,4\"\"\"F-*&#F-\"\"#F-9$F-!\"\"*&#\"\"&\"\")F-*$)F1F0F-F-F2*&#\"#@ \"#;F-*$)F1\"\"$F-F-F2*&#\"$H%\"$G\"F-*$)F1\"\"%F-F-F2*&#\"%JC\"$c#F-* $)F1F5F-F-F2*&#\"&$RH\"%C5F-*$)F1\"\"'F-F-F2*&#\"'Dd=\"%[?F-*$)F1\"\"( F-F-F2*&#\"(X[p*\"&oF$F-*$)F1F6F-F-F2F(F(F(" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "T := 0.1:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "fD(T);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#$\"+;lm>%*!#5" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "fA(T);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#$\"+]WWW%*!#5" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "pT := subs(t=T,p);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#pTG7$,& *&&%\"xG6#\"\"\"F+&F)6#\"\"#F+F+F+!\"\",(*$)F(F.F+F+*&$F+F/F+)F,F.F+F+ F+F/" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 45 "sols := fsolve(\{op (pT)\},\{x[1]=1.0,x[2]=1.0\});" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%%s olsG<$/&%\"xG6#\"\"\"$\"+^9l>%*!#5/&F(6#\"\"#$\"+1/hh5!\"*" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "assign(sols);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "fA(T) - x[1];" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#$\")**HzC!#5" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "fD(T) - x[1];" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#$\"&l]\"!#5" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 96 "Even for a large value of t, the last pow er series give us five correct decimal places for x[1]." }{MPLTEXT 1 0 0 "" }}}}{MARK "4 0 1" 0 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 } {PAGENUMBERS 0 1 2 33 1 1 }{RTABLE_HANDLES 136552128 137760700 } {RTABLE M7R0 I6RTABLE_SAVE/136552128X,%)anythingG6"6"[gl!"%!!!#%"#"#&%"xG6#""#,$&F(6#"""F*F, ,$*&%"tGF.F'F.F*6" } {RTABLE M7R0 I6RTABLE_SAVE/137760700X,%)anythingG6"6"[gl!"%!!!#%"#"#"""""#F',$%"tGF(6" }