dim v(70,450) as double

dim v1(70,450) as double
dim v2(70,450) as double
dim v3(70,450) as double
dim v4(70,450) as double
dim v5(70,450) as double

dim alph as double
dim beta as double

dim weight as double

dim count as integer

dim check as integer

dim con as integer

dim x as integer
dim y as integer

dim track as integer
dim e1 as double
dim e2 as double


weight = 0.1

open "2dacceltestw0p1c.csv" for output as #1



for x = 1 to 70
    for y = 0 to 450 
    v(x,y) = 0
    next
next




track = 1

again:

for count = track to track+5
    
    for x = 2 to 69
        for y = 1 to 449
        
        v5(x,y) = (v(x-1,y) + v(x+1,y)+v(x,y-1)+v(x,y+1)+1)/4
        next
    next
    
    for y = 1 to 449
        v5(1,y) = v(2,y)
        v5(70,y) = v(69,y)
    next
    
    for x = 1 to 70
        v5(x,450) = v(x,449)
    next
    
    
    print #1, count;",";v5(35,1);",";v5(35,450)
    
    for x = 1 to 70
        for y = 1 to 450
        
        v1(x,y) = v2(x,y)
        v2(x,y) = v3(x,y)
        v3(x,y) = v4(x,y)
        v4(x,y) = v5(x,y)
        v(x,y) = v5(x,y)
        next
    next
    
next

track = track + 6

count = track

con = 0

do

    if track / 100 = int(track/100) then print track

    for x = 2 to 69
        for y = 1 to 449
        
        v5(x,y) = (v(x-1,y) + v(x+1,y)+v(x,y-1)+v(x,y+1)+1)/4
        next
    next
    
    for y = 1 to 449
        v5(1,y) = v(2,y)
        v5(70,y) = v(69,y)
    next
    
    for x = 1 to 70
        v5(x,450) = v(x,449)
    next
    
    
   
    
    for x = 1 to 70
        for y = 1 to 450
        
        v1(x,y) = v2(x,y)
        v2(x,y) = v3(x,y)
        v3(x,y) = v4(x,y)
        v4(x,y) = v5(x,y)
        v(x,y) = v5(x,y)
        next
    next
    

    check = 1
    
    
    for x = 1 to 70
        for y = 1 to 450
        
        if (v4(x,y)-v3(x,y))/(v2(x,y)-v1(x,y)) >= 0 then
            alph = sqr((v4(x,y)-v3(x,y))/(v2(x,y)-v1(x,y)))
            if alph >= 1 then check = 0
            if alph <= -1 then check = 0
        else 
            check = 0
        end if
        
        
        next
    
    next
    
    if check = 1 then con = con + 1
    if check = 0 then con = 0

    print #1, count;",";v(35,1);",";v(35,450)
    
    count = count + 1
    track = track + 1

loop until con >= 450 or count > 200000

if count > 200000 then goto finish 
    
    
REM Extrapolation step

for x = 1 to 70
    for y = 1 to 450
    
        
    alph = sqr((v5(x,y)-v4(x,y))/(v3(x,y)-v2(x,y)))
    
    beta = (v5(x,y)+v4(x,y)+v3(x,y))/3 - (v4(x,y)+v3(x,y)+v2(x,y))*alph/3
    
    e1 = beta/(1-alph)
    
        
    alph = sqr((v4(x,y)-v3(x,y))/(v2(x,y)-v1(x,y)))
    
    beta = (v4(x,y)+v3(x,y)+v2(x,y))/3 - (v3(x,y)+v2(x,y)+v1(x,y))*alph/3
    
    e2 = beta/(1-alph)
    
    v(x,y) = (2-weight)/(weight/v(x,y) + (1-weight)*(1/e1+1/e2))
    next
next


    print #1, count;",";v(35,1);",";v(35,450)
    
    count = count + 1
    track = track + 1
    
    goto again
    
    finish:
    
    close #1