taichi-dev/taichi

Reverse NDRange support

Open

#4,379 opened on Feb 24, 2022

View on GitHub
 (9 comments) (4 reactions) (1 assignee)C++ (2,384 forks)batch import
feature requestgood first issuewelcome contribution

Repository metrics

Stars
 (28,195 stars)
PR merge metrics
 (No merged PRs in 30d)

Description

There comes one special case which requires a reverse loop, so I used “ti.ndrange(8,0)” instead. However, the reverse loop just didn’t work with zero warnings or errors (I have no idea whether ti.ndrange can be used to loop in reverse order at that time) Perhaps a warning message can be given when n1 > n2 in ti.ndrange((n1,n2))

import taichi as ti
ti.init(arch=ti.gpu, debug=True, default_fp=ti.f64)

x = ti.field(ti.f64, shape=(10))

@ti.kernel
def main():
    x[9] = 1.0
    for i in ti.ndrange((8,0)):
        x[i] = 2.0 * x[i+1]
        print(x[i])    #print nothing

main()

Contributor guide

Research direction
Investigate how ti.ndrange handles reversed ranges. The current behavior silently produces no iterations. Implement a warning when n1 > n2 or support reverse iteration.
Tech stack
python
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Python
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70