CODEWITHSUNDEEP
php
Ugy Astro
Ugy Astro

Reputation: 417

php based Neural Network — how to implement backpropagation

nothing is ever simple for bacpropagation with php? or examples of the case of solving problem XOR? whether you want to share?

I've created, XOR, too, just not maximized. this, declaration variable type double in the php there is do not rules?? because i have a problem when the variable whose value -5.92878775009E-323 multiplied by (*) 0.00310811260635 is 0;

I tried in excel too, error / zero, meaning the problem is of variable length that I specify, while the variable I declared value "null" as "public w = null". sorry a lot of questions ..

thanks if you want to answer my questions..

Upvotes: 0

Views: 1074

Answers (1)

Robert Seddon-Smith
Robert Seddon-Smith

Reputation: 1002

-5.92878775009E-323 is such a ridiculously small number that it will compute as zero. The best way to handle this is to use standard exponent mathematics.

I would handle this by multiplying the digits then summing the exponents in a custom function. That having been said, if you need to manage these numbers, you are probably already losing a lot of information in the rounding to 12 significant figures.

If you need to do this without loss of data, the only way I can think of doing it is to use the computer to do the multiplication much in the same way it is handled on paper, one digit at a time.

Why not write a function like this?

Alternatively, if you are not feeling suicidal, try bcmul() which is a PHP function that does exactly what you need.

Upvotes: 1

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