gd_tests
Tests about Gradient Descent, but really performance, optimizer, and ASM tests
Constants
function : f(x) = (x-5)^2+7 alpha = 0.5 delta: 0.01 (used as pseudo infinitesimal for gradient calculation) initial point: 1.0 iterations: 1000000000 ( 1 billion )
Speed
| Method | Description | Time:user |
|---|---|---|
| c, gcc -O0 | c, not optimized | 0m33.972s |
| c, gcc -O1 | c, Moderate optimization; optimizes reasonably well but does not degrade compilation time significantly. |
0m15.334s |
| c, gcc -O2 | c, Full optimization; generates highly optimized code and has the slowest compilation time. |
0m10.553s |
| c, gcc -O3 | c, Full optimization as in -O2; also uses more aggressive automatic inlining of subprograms within a unit (Inlining of Subprograms) and attempts to vectorize loops. |
0m10.353s |
| asm, linear | Performing same calculations with pared down linear hand-written assembly | 0m0.498s |
Going forward
This isn't a fair comparison, but I managed to be faster(?). If I didn't have it output the value, O2 and O3 would optimize it away, but there's no equivalent copy from register to STDOUT in my asm file. Also, the asm code is as pared down as possible, to the point of not properly using stack frames, and instead abusing the floating point stack. I don't think I'll continue down this avenue, at least until I do more x86 asm.
Links
GCC Optimization Flag quotes - https://gcc.gnu.org/onlinedocs/gnat_ugn/Optimization-Levels.html