Can not print to debug in the first field -> 'NoneType' object has no attribute 'data_type'

[yihong0618]

Describe the bug
Can not print to debug in the first field

To Reproduce

not work

import math

import taichi as ti

ti.init(arch=[ti.cuda, ti.metal])

dim = 3
N = 1024 * 8
dt = 2e-4
steps = 7
sun = ti.Vector([0.5, 0.5] if dim == 2 else [0.5, 0.5, 0.0])
gravity = 0.5
pressure = 0.3
tail_paticle_scale = 0.4
color_init = 0.3
color_decay = 1.6
vel_init = 0.07
res = 640

inv_m = ti.field(ti.f32)
color = ti.field(ti.f32)
x = ti.Vector.field(dim, ti.f32)
v = ti.Vector.field(dim, ti.f32)
print(v)
ti.root.bitmasked(ti.i, N).place(x, v, inv_m, color)
count = ti.field(ti.i32, ())
img = ti.field(ti.f32, (res, res))

work

import math

import taichi as ti

ti.init(arch=[ti.cuda, ti.metal])

dim = 3
N = 1024 * 8
dt = 2e-4
steps = 7
sun = ti.Vector([0.5, 0.5] if dim == 2 else [0.5, 0.5, 0.0])
gravity = 0.5
pressure = 0.3
tail_paticle_scale = 0.4
color_init = 0.3
color_decay = 1.6
vel_init = 0.07
res = 640

inv_m = ti.field(ti.f32)
color = ti.field(ti.f32)
x = ti.Vector.field(dim, ti.f32)
v = ti.Vector.field(dim, ti.f32)
ti.root.bitmasked(ti.i, N).place(x, v, inv_m, color)
count = ti.field(ti.i32, ())
img = ti.field(ti.f32, (res, res))
print(v)

Log/Screenshots

env

win10 python3.8.5

[Taichi] version 0.7.32, llvm 10.0.0, commit 6652f94f, win, python 3.8.5

[strongoier]

Nice catch! The fields are fully constructed during place() so we could only print after it. But we indeed need to provide better error message. Thanks for telling us about this.

[yihong0618]

@strongoier

I think so~Maybe give a default initialisation value or type?

[strongoier]

A field needs a shape to become meaningful. Shape info is only contained in ti.root.bitmasked(ti.i, N).place(x, v, inv_m, color). So if printed, it should show something like The definition of the field is incomplete.

[yihong0618]

Cool.

Got it.

[yihong0618]

Cool