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Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed
From: |
al davis |
Subject: |
Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed |
Date: |
Fri, 12 May 2006 18:34:48 -0400 |
User-agent: |
KMail/1.9.1 |
On Friday 12 May 2006 17:56, Achilleas Anastasopoulos wrote:
> you can find the relevant code here:
>
> http://www.eecs.umich.edu/~anastas/gnuradio/
>
> looking forward to your comments.
You are returning a vector by value:
from fsm.h:
//========
std::vector<int> NS () const { return d_NS; }
std::vector<int> OS () const { return d_OS; }
std::vector<int> PS () const { return d_PS; }
std::vector<int> PI () const { return d_PI; }
//========
inside a loop, double nested:
from: howto_trellis_encoder_si.cc
===============
for (int m=0;m<nstreams;m++) {
// stuff deleted
for (int i = 0; i < noutput_items; i++){
out[i] = (int) d_FSM.OS()[d_ST_tmp*d_FSM.I()+in[i]];
d_ST_tmp = (int) d_FSM.NS()[d_ST_tmp*d_FSM.I()+in[i]];
}
===============
I am amazed that you are only getting a 5-fold reduction!
A few years ago, I made some tests, in gnucap. I found that in
all tests there was no run time speed penalty for using STL,
even in speed critical tight loops. By using it, I was able to
do things that would have been impractical without it,
resulting in a net speed improvement. Compiling is slower, but
I can live with that.
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, (continued)
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Achilleas Anastasopoulos, 2006/05/12
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Eric Blossom, 2006/05/13
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Achilleas Anastasopoulos, 2006/05/14
- Message not available
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Achilleas Anastasopoulos, 2006/05/14
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Eric Blossom, 2006/05/14
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Eric Blossom, 2006/05/14
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Dave Dodge, 2006/05/15
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed,
al davis <=
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, al davis, 2006/05/12
- Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Eric Blossom, 2006/05/13
Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Eric Blossom, 2006/05/13
Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Achilleas Anastasopoulos, 2006/05/13
Re: [Discuss-gnuradio] ANCI-C vs Gnuradio/C++ speeeed, Achilleas Anastasopoulos, 2006/05/13