In maple i'm using 2D input so fn_i is being evaluated as a index, so I don't think that's the problem. Is seq the correct command to generate a system of equations like this?

The text looks a little weird to me aswell, I thought it was just because I was using linux. Here's it in normal text:

rho_in := fp_5 + fp_7 + fp_8

rho_out := fn_4 + fn_6 + fn_9

massconserv := rho_in = rho_out

w:= [ 4/9, 1/9, 1/9, 1/9, 1/9, 1/36, 1/36, 1/36, 1/36 ]

feq := i-> rho_wall * w[i]

col := seq(fn_i = (1-1/tau)*fp_i + 1/tau * feq(i), i = 1..9)

solve( { massconserv, col }, { fp_4, fp_5, fp_6, fp_7, fp_8, fp_9, rho_wall } )

In maple i'm using 2D input so fn_i is being evaluated as a index, so I don't think that's the problem. Is seq the correct command to generate a system of equations like this?

The text looks a little weird to me aswell, I thought it was just because I was using linux. Here's it in normal text:

rho_in := fp_5 + fp_7 + fp_8

rho_out := fn_4 + fn_6 + fn_9

massconserv := rho_in = rho_out

w:= [ 4/9, 1/9, 1/9, 1/9, 1/9, 1/36, 1/36, 1/36, 1/36 ]

feq := i-> rho_wall * w[i]

col := seq(fn_i = (1-1/tau)*fp_i + 1/tau * feq(i), i = 1..9)

solve( { massconserv, col }, { fp_4, fp_5, fp_6, fp_7, fp_8, fp_9, rho_wall } )