Improve garbage collection

[lucifer1004]

Currently, Taichi does not seem to reclaim unusable fields.

For example, the following code can easily lead to OOM.

import taichi as ti

ti.init(arch=ti.vulkan)


@ti.data_oriented
class Container:
    def __init__(self):
        self.f = ti.field(ti.f32, shape=100000000)

    @ti.kernel
    def do(self):
        for i in self.f:
            self.f[i] = i


for i in range(100):
    Container().do()

And this could be solved by calling ti.init() multiple times:

import taichi as ti


@ti.data_oriented
class Container:
    def __init__(self):
        self.f = ti.field(ti.f32, shape=100000000)

    @ti.kernel
    def do(self):
        for i in self.f:
            self.f[i] = i


for i in range(100):
    ti.init(arch=ti.vulkan)
    Container().do()

Despite the workaround, I think it is worth that Taichi could do some garbage collection. In the example above, it should be easy to figure out that the Container instance created in one loop will not be used any more.

[lin-hitonami]

Taichi does not have automatic garbage collection for fields right now, but you can allocate and destroy fields manually using FieldsBuilder. See https://docs.taichi-lang.org/docs/layout#manual-field-allocation-and-destruction for more information.