Thur., Nov 7, 2013

Pin Yi Tsai

WEEKLY REPORT

OUTLINE

• Current Work• New Method

• Compute Integral Image – computeByRow unknown problem

• How to Debug? Nsight

NEW METHOD

• Previous Version:

• One line per thread

• Take too much time on accessing inconsistent memory

• New one:

• One pixel per thread

• Using shared memory to store the middle value

NEW METHOD (CONT.)

• Shared memory: store the values of the previous line

• computing by Row for img[*][y] and img[*][y+1]

• Time t: calculate img[*][y] + shared memory[*]

• Then store the result back to shared memory[*]

• Time t+1: calculate img[*][y+1] + shared memory[*]

COMPUTE INTEGRAL IMAGE – COMPUTE_BY_ROW

• Original Input

COMPUTE INTEGRAL IMAGE (CONT.)

• Correct Output – Compute By Row

COMPUTE INTEGRAL IMAGE (CONT.)

• With problems

HOW TO DEBUG ?

• Nsight ─ an IDE for developers building CUDA application ─ able to Profile and observe the value of each thread

• In process:

• Compile with custom makefile

HOW TO DEBUG ? (CONT.)

The End