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20131024

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Published on

2013/10/24 …

2013/10/24
meeting at Delta R621

Published in: Technology, Education
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Transcript

  1. WEEKLY REPORT Thur., Oct 24, 2013 Pin Yi Tsai
  2. OUTLINE • Current Work • Compute Integral Image – parallel version • Why the difference is so implicit? • An accidental Error • In Process • Compute 11 types of Features
  3. COMPUTE INTEGRAL IMAGE – PARALLEL VERSION • Computation and communication time  input 16x16:  serial version: 0.006336 ms  for loop outside of kernel function:  parallel version: 6.80778 ms  for loop inside of kernel function:  parallel version: 5.88559e-39 ms
  4. COMPUTE INTEGRAL IMAGE (CONT.)  input 640x480:  serial version: 5.1607 ms  parallel version: 4.94058 ms
  5. WHY THE DIFFERENCE IS SO IMPLICIT? • Profile: Time : 4.91024 ms ======== Profiling result: Time(%) 71.71 Time Calls 2.75ms 1 Avg 2.75ms Min 2.75ms Max Name 2.75ms computeByColumn(float*, int) 10.91 418.56us 2 209.28us 209.06us 209.50us [CUDA memcpy HtoD] 10.08 386.46us 2 193.23us 191.10us 195.36us [CUDA memcpy DtoH] 7.31 280.22us int) 1 280.22us 280.22us 280.22us computeByRow(float*, int,  Access the inconsistent memory  Memory Access is too time-consuming
  6. AN ACCIDENTAL ERROR • Occurred when copy data from Mat to one-dimension float array 0 175 175 175 175 175 0 174 174 174 174 174 6.78807e-29 175 175 175 175 175 0 175 175 175 175 175 0 175 175 175 175 175 6.79909e-29 134 151 158 136 142 0 138 132 135 140 135 6.80354e-29 136 136 143 142 137
  7. AN ACCIDENTAL ERROR (CONT.) • Why? • memset(ar,0,sizeof(float)*(image1.step+1)*(image1.rows+1)); • The size is not correct.
  8. The End

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