Author: Vincent Diepeveen
Date: 05:07:58 07/05/01
Hi, risking to be off topic, here a small attempt to adress the intel c++ compiler 5.01 build 15 I tried several options with it for DIEP and figured out that it is 1.5% slower for me as msvc 6.0, nevertheless that's very good considering that 5.00 completely crashed. this version does *not* crash. it produces an exe which runs and which doesn't crash. I measured however in another program of mine some weird things in floating point unit calculations. An AI program of mine, which fiddles with parameters (neural based) is regrettably no longer deterministic. When i use optimizations -O3 and some optimizations that allow Pentiumpro instructions and MMX and SSE and similar instructions, then i get completely different results. Especially the function y = ax^2 + bx + c which i use everywhere in the network, is giving different results when using different optimizations. This is a bad thing! I cannot explain it but i feel that it has to do with the fact that all these values are 'float'. Then when casting them back to parameters in 1/1000 pawn, i get differences in testruns of up to 1 millipawn for the average calculation! This is WEIRD!!!!!!!!!!!!!!!!!!!!!!!! I cannot explain it!!!!!!!!!!!!!1 So i cannot use this compiler. Note that i find it pretty bad that a compiler which was already very good some time ago, that it still can't beat at a P3-800, which is an intel chip, the visual c++ compiler. It was 0.5% slower this intel c++ some years ago as visual. Latest visual c++ compiler is 1.5% faster, despite that it has all kind of instructions nowadays this intel c++! Using all those instructions it's NOT giving deterministic results. If i turn off those P3 instructions, then it is of course going to be hell slower as visual. Nevertheless it's a good thing that it no longer crashes like version 5.00 Best regards, Vincent
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