.MCAD 304020000 1 74 46 0 .CMD PLOTFORMAT 0 0 1 1 1 0 0 1 1 0 0 1 1 1 0 0 1 1 0 1 0 0 1 1 NO-TRACE-STRING 0 2 1 0 1 1 NO-TRACE-STRING 0 3 2 0 1 1 NO-TRACE-STRING 0 4 3 0 1 1 NO-TRACE-STRING 0 1 4 0 1 1 NO-TRACE-STRING 0 2 5 0 1 1 NO-TRACE-STRING 0 3 6 0 1 1 NO-TRACE-STRING 0 4 0 0 1 1 NO-TRACE-STRING 0 1 1 0 1 1 NO-TRACE-STRING 0 2 2 0 1 1 NO-TRACE-STRING 0 3 3 0 1 1 NO-TRACE-STRING 0 4 4 0 1 1 NO-TRACE-STRING 0 1 5 0 1 1 NO-TRACE-STRING 0 2 6 0 1 1 NO-TRACE-STRING 0 3 0 0 1 1 NO-TRACE-STRING 0 4 1 0 1 1 NO-TRACE-STRING 0 1 1 21 15 0 0 3 .CMD FORMAT rd=d ct=10 im=i et=3 zt=15 pr=3 mass length time charge temperature tr=0 vm=0 .CMD SET ORIGIN 0 .CMD SET TOL 0.001000000000000 .CMD SET PRNCOLWIDTH 8 .CMD SET PRNPRECISION 4 .CMD PRINT_SETUP 1.200000 1.218750 1.200000 1.200000 0 .CMD HEADER_FOOTER 1 1 *empty* *empty* *empty* 0 1 *empty* *empty* *empty* .CMD HEADER_FOOTER_FONT fontID=14 family=Arial points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD HEADER_FOOTER_FONT fontID=15 family=Arial points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFAULT_TEXT_PARPROPS 0 0 0 .CMD DEFINE_FONTSTYLE_NAME fontID=0 name=Variables .CMD DEFINE_FONTSTYLE_NAME fontID=1 name=Constants .CMD DEFINE_FONTSTYLE_NAME fontID=2 name=Text .CMD DEFINE_FONTSTYLE_NAME fontID=4 name=User^1 .CMD DEFINE_FONTSTYLE_NAME fontID=5 name=User^2 .CMD DEFINE_FONTSTYLE_NAME fontID=6 name=User^3 .CMD DEFINE_FONTSTYLE_NAME fontID=7 name=User^4 .CMD DEFINE_FONTSTYLE_NAME fontID=8 name=User^5 .CMD DEFINE_FONTSTYLE_NAME fontID=9 name=User^6 .CMD DEFINE_FONTSTYLE_NAME fontID=10 name=User^7 .CMD DEFINE_FONTSTYLE fontID=0 family=Times^New^Roman points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=1 family=Times^New^Roman points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=2 family=Arial points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=4 family=Arial points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=5 family=Courier^New points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=6 family=System points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=7 family=Script points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=8 family=Roman points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=9 family=Modern points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD DEFINE_FONTSTYLE fontID=10 family=Times^New^Roman points=10 bold=0 italic=0 underline=0 colrid=-1 .CMD UNITS U=1 .CMD DIMENSIONS_ANALYSIS 0 0 .CMD COLORTAB_ENTRY 0 0 0 .CMD COLORTAB_ENTRY 128 0 0 .CMD COLORTAB_ENTRY 0 128 0 .CMD COLORTAB_ENTRY 128 128 0 .CMD COLORTAB_ENTRY 0 0 128 .CMD COLORTAB_ENTRY 128 0 128 .CMD COLORTAB_ENTRY 0 128 128 .CMD COLORTAB_ENTRY 128 128 128 .CMD COLORTAB_ENTRY 192 192 192 .CMD COLORTAB_ENTRY 255 0 0 .CMD COLORTAB_ENTRY 0 255 0 .CMD COLORTAB_ENTRY 255 255 0 .CMD COLORTAB_ENTRY 0 0 255 .CMD COLORTAB_ENTRY 255 0 255 .CMD COLORTAB_ENTRY 0 255 255 .CMD COLORTAB_ENTRY 255 255 255 .CMD COLORTAB_ENTRY 0 64 128 .TXT 2 3 26 0 0 Cg a71.000000,71.000000,1257 {\rtf\ansi \deff0{\colortbl;\red0\green0\blue128;\red0\green0\blue255; \red255\green0\blue255;}{\fonttbl{\f0\fcharset0\fnil Arial;}}\plain\cf1 \fs20 \pard {\cf2\fs28 An important example of deterministic chaos is the weather. The forecasts are never for more than a few days into the future. This is }{\cf2\fs28\b not}{\cf2\fs28 because our models of the weather are not complete. More powerful supercomputers and even more complicated models will not help much with the long term weather forecasts. }{\cf3\fs28 Edward Lorenz}{\cf2\fs28 , an MIT meteorologist, showed this is the case in his influential paper }{\cf2 \fs28\i "Deterministic Nonperiodic Flow"}{\cf2\fs28 published in 1963 in the Journal of Atmospheric Science. The weather is chaotic. Even with a perfect model of the weather it is not possible to predict it very far into the future. The reason is the so-called }{\cf2\fs28\i butterfly effect}{\cf2\fs28 , a name coined by }{\cf3\fs28 Lorenz}{\cf2 \fs28 . Let us assume that we have a good model of the weather. To use it to predict the future weather conditions we have to know the }{\cf2 \fs28\i initial conditions, i.e. }{\cf2\fs28 the weather conditions today. }{\cf3\fs28 Lorenz}{\cf2\fs28 showed that for a particular model of atmospheric convection two }{\cf2\fs28\b initial conditions different by very little lead to two very different long-term predictions}{ \cf2\fs28 . In this file we use the Euler approximation to integrate the three differental equations that Lorenz used to model atmospheric convection. The strange attractor shown in the last graph is a fractal called Lorenz butterfly. }} .TXT 51 34 41 0 0 Cg a37.000000,37.000000,11 {\rtf\ansi \deff0{\colortbl;\red0\green0\blue128;}{\fonttbl{\f0 \fcharset0\fnil Arial;}}\plain\cf1\fs20 \pard Parameters:} .TXT 1 -23 35 0 0 Cg a60.000000,60.000000,18 {\rtf\ansi \deff0{\colortbl;\red0\green0\blue128;}{\fonttbl{\f0 \fcharset0\fnil Arial;}}\plain\cf1\fs20 \pard Initial conditions} .EQN 0 35 39 0 0 {0:\s}NAME:10 .EQN 0 10 40 0 0 {0:r}NAME:24.74 .EQN 0 7 38 0 0 {0:b}NAME:(8)/(3) .EQN 2 -62 17 0 0 ({3,1}ö({0:z}NAME)[(0)ö({0:y}NAME)[(0)ö({0:x}NAME)[(0)):({3,1}ö0ö20ö0) .EQN 7 -1 45 0 0 {0:\Dt}NAME:.0025 .TXT 0 13 43 0 0 Cg a58.000000,58.000000,13 {\rtf\ansi \deff0{\colortbl;\red0\green0\blue128;}{\fonttbl{\f0 \fcharset0\fnil Arial;}}\plain\cf1\fs20 \pard Time interval} .EQN 3 -13 46 0 0 {0:t}NAME:0;10000 .TXT 0 13 44 0 0 Cg a58.000000,58.000000,22 {\rtf\ansi \deff0{\colortbl;\red0\green0\blue128;}{\fonttbl{\f0 \fcharset0\fnil Arial;}}\plain\cf1\fs20 \pard Number of integrations} .EQN 7 -5 15 0 0 ({3,1}ö({0:z}NAME)[({0:t}NAME+1)ö({0:y}NAME)[({0:t}NAME+1)ö({0:x}NAME)[({0:t}NAME+1)):({3,1}ö({0:z}NAME)[({0:t}NAME)*(1-{0:\Dt}NAME*{0:b}NAME)+{0:\Dt}NAME*({0:x}NAME)[({0:t}NAME)*({0:y}NAME)[({0:t}NAME)ö({0:y}NAME)[({0:t}NAME)*(1-{0:\Dt}NAME)+({0:x}NAME)[ ({0:t}NAME)*{0:\Dt}NAME*({0:r}NAME-({0:z}NAME)[({0:t}NAME))ö({0:x}NAME)[({0:t}NAME)*(1-{0:\Dt}NAME*{0:\s}NAME)+{0:\Dt}NAME*{0:\s}NAME*({0:y}NAME)[({0:t}NAME)) .EQN 10 -10 21 0 0 &&(_n_u_l_l_&_n_u_l_l_)&({0:z}NAME)[({0:t}NAME)@&&(_n_u_l_l_&_n_u_l_l_)&({0:y}NAME)[({0:t}NAME) 0 0 1 1 1 0 0 1 1 0 0 1 1 1 0 0 1 1 0 1 0 0 1 1 NO-TRACE-STRING 0 2 1 0 1 1 NO-TRACE-STRING 0 3 2 0 1 1 NO-TRACE-STRING 0 4 3 0 1 1 NO-TRACE-STRING 0 1 4 0 1 1 NO-TRACE-STRING 0 2 5 0 1 1 NO-TRACE-STRING 0 3 6 0 1 1 NO-TRACE-STRING 0 4 0 0 1 1 NO-TRACE-STRING 0 1 1 0 1 1 NO-TRACE-STRING 0 2 2 0 1 1 NO-TRACE-STRING 0 3 3 0 1 1 NO-TRACE-STRING 0 4 4 0 1 1 NO-TRACE-STRING 0 1 5 0 1 1 NO-TRACE-STRING 0 2 6 0 1 1 NO-TRACE-STRING 0 3 0 0 1 1 NO-TRACE-STRING 0 4 1 0 1 1 NO-TRACE-STRING 0 1 1 62 15 10 0 3 .EQN 24 0 23 0 0 &&(_n_u_l_l_&_n_u_l_l_)&({0:x}NAME)[({0:t}NAME)@&&(_n_u_l_l_&_n_u_l_l_)&({0:y}NAME)[({0:t}NAME) 0 0 1 1 1 0 0 1 1 0 0 1 1 1 0 0 1 1 0 1 0 0 1 1 NO-TRACE-STRING 0 2 1 0 1 1 NO-TRACE-STRING 0 3 2 0 1 1 NO-TRACE-STRING 0 4 3 0 1 1 NO-TRACE-STRING 0 1 4 0 1 1 NO-TRACE-STRING 0 2 5 0 1 1 NO-TRACE-STRING 0 3 6 0 1 1 NO-TRACE-STRING 0 4 0 0 1 1 NO-TRACE-STRING 0 1 1 0 1 1 NO-TRACE-STRING 0 2 2 0 1 1 NO-TRACE-STRING 0 3 3 0 1 1 NO-TRACE-STRING 0 4 4 0 1 1 NO-TRACE-STRING 0 1 5 0 1 1 NO-TRACE-STRING 0 2 6 0 1 1 NO-TRACE-STRING 0 3 0 0 1 1 NO-TRACE-STRING 0 4 1 0 1 1 NO-TRACE-STRING 0 1 1 61 12 10 0 3 .EQN 21 1 24 0 0 &&(_n_u_l_l_&_n_u_l_l_)&({0:x}NAME)[({0:t}NAME),({0:y}NAME)[({0:t}NAME),({0:z}NAME)[({0:t}NAME)@&&(_n_u_l_l_&_n_u_l_l_)&{0:t}NAME 0 0 1 1 1 0 0 1 1 0 0 1 1 1 0 0 1 1 0 1 0 0 1 1 NO-TRACE-STRING 0 2 1 0 1 1 NO-TRACE-STRING 0 3 2 0 1 1 NO-TRACE-STRING 0 4 3 0 1 1 NO-TRACE-STRING 0 1 4 0 1 1 NO-TRACE-STRING 0 2 5 0 1 1 NO-TRACE-STRING 0 3 6 0 1 1 NO-TRACE-STRING 0 4 0 0 1 1 NO-TRACE-STRING 0 1 1 0 1 1 NO-TRACE-STRING 0 2 2 0 1 1 NO-TRACE-STRING 0 3 3 0 1 1 NO-TRACE-STRING 0 4 4 0 1 1 NO-TRACE-STRING 0 1 5 0 1 1 NO-TRACE-STRING 0 2 6 0 1 1 NO-TRACE-STRING 0 3 0 0 1 1 NO-TRACE-STRING 0 4 1 0 1 1 NO-TRACE-STRING 0 1 1 61 17 10 0 3 .EQN 30 -1 25 0 0 {0:x}NAME,{0:y}NAME,{0:z}NAME{3 5 3 10 35 0 71 30 0 1 1 1 4 -1 1 0 1 1 1 4 -1 1 0 1 1 1 4 -1 1 5 0 16777215 1 100 2 NO-TITLE}{57} 2 5 21 21 0 1 1.5 7 1 1 4 2 1 4 1 4 3 1 2 0.1