SigmoidFunction.php

<?php
//https://en.wikipedia.org/wiki/Sigmoid_function
function Sigmoid($t){
    return 1 / (1 + exp(-$t)); // Output 0 to 1
}

function SigmoidSymmetric($t){
    return 2 / (1 + exp(-$t)) - 1; // Output -1 to 1
}

// Alternative SigmoidSymmetric TanH()
function HyperbolicTangent($t){
 return (exp($t) - exp(-$t)) / (exp($t) + exp(-$t)); // -1 to 1
}


$test_results = array();
for ($i = -5.00; $i < 5.00; $i+= 0.1){
	array_push($test_results, Sigmoid($i));
}
var_dump($test_results);


/*
Results of Simoid Function:

0.0066928509242849 
0.007391541344282 
0.0081625711531599 
0.0090132986528478 
0.0099518018669043 
0.010986942630593 
0.012128434984274 
0.013386917827665 
0.014774031693273 
0.016302499371441 
0.017986209962091 
0.019840305734077 
0.02188127093613 
0.024127021417669 
0.026596993576866 
0.029312230751356 
0.03229546469845 
0.035571189272636 
0.039165722796764 
0.043107254941086 
0.047425873177567 
0.052153563078418 
0.057324175898869 
0.062973356056996 
0.069138420343347 
0.075858180021243 
0.083172696493922 
0.091122961014856 
0.099750489119685 
0.10909682119561 
0.11920292202212 
0.130108474363 
0.14185106490049 
0.15446526508353 
0.16798161486608 
0.18242552380636 
0.19781611144142 
0.21416501695744 
0.23147521650098 
0.24973989440488 
0.26894142136999 
0.289050497375 
0.31002551887239 
0.33181222783183 
0.3543436937742 
0.37754066879815 
0.40131233988755 
0.42555748318834 
0.45016600268752 
0.47502081252106 
0.5 
0.52497918747894 
0.54983399731248 
0.57444251681166 
0.59868766011245 
0.62245933120185 
0.6456563062258 
0.66818777216817 
0.68997448112761 
0.710949502625 
0.73105857863 
0.75026010559512 
0.76852478349902 
0.78583498304256 
0.80218388855858 
0.81757447619364 
0.83201838513392 
0.84553473491647 
0.85814893509951 
0.869891525637 
0.88079707797788 
0.89090317880439 
0.90024951088031 
0.90887703898514 
0.91682730350608 
0.92414181997876 
0.93086157965665 
0.937026643943 
0.94267582410113 
0.94784643692158 
0.95257412682243 
0.95689274505891 
0.96083427720324 
0.96442881072736 
0.96770453530155 
0.97068776924864 
0.97340300642313 
0.97587297858233 
0.97811872906387 
0.98015969426592 
0.98201379003791 
0.98369750062856 
0.98522596830673 
0.98661308217234 
0.98787156501573 
0.98901305736941 
0.9900481981331 
0.99098670134715 
0.99183742884684 
0.99260845865572 
0.99330714907572
*/

$test_results = array();
for ($i = -5.00; $i < 5.00; $i+= 0.1){
	array_push($test_results, SigmoidSymmetric($i));
}
var_dump($test_results);

/*
Results of Simoid Symmetric Function:

-0.98661429815143
-0.98521691731144
-0.98367485769368
-0.9819734026943
-0.98009639626619
-0.97802611473881
-0.97574313003145
-0.97322616434467
-0.97045193661345
-0.96739500125712
-0.96402758007582
-0.96031938853185
-0.95623745812774
-0.95174595716466
-0.94680601284627
-0.94137553849729
-0.9354090706031
-0.92885762145473
-0.92166855440647
-0.91378549011783
-0.90514825364487
-0.89569287384316
-0.88535164820226
-0.87405328788601
-0.86172315931331
-0.84828363995751
-0.83365460701216
-0.81775407797029
-0.80049902176063
-0.78180635760877
-0.76159415595577
-0.739783051274
-0.71629787019902
-0.69106946983293
-0.66403677026785
-0.63514895238729
-0.60436777711716
-0.57166996608512
-0.53704956699804
-0.50052021119024
-0.46211715726001
-0.42189900525001
-0.37994896225523
-0.33637554433633
-0.29131261245159
-0.24491866240371
-0.1973753202249
-0.14888503362332
-0.099667994624956
-0.04995837495788
-4.4408920985006E-16
0.049958374957879
0.099667994624955
0.14888503362332
0.1973753202249
0.24491866240371
0.29131261245159
0.33637554433633
0.37994896225522
0.42189900525001
0.46211715726001
0.50052021119023
0.53704956699803
0.57166996608512
0.60436777711716
0.63514895238729
0.66403677026785
0.69106946983293
0.71629787019902
0.739783051274
0.76159415595576
0.78180635760877
0.80049902176063
0.81775407797029
0.83365460701216
0.84828363995751
0.86172315931331
0.87405328788601
0.88535164820226
0.89569287384316
0.90514825364487
0.91378549011783
0.92166855440647
0.92885762145473
0.9354090706031
0.94137553849729
0.94680601284627
0.95174595716466
0.95623745812774
0.96031938853185
0.96402758007582
0.96739500125712
0.97045193661345
0.97322616434467
0.97574313003145
0.97802611473881
0.98009639626619
0.9819734026943
0.98367485769368
0.98521691731144
0.98661429815143
	
*/


$test_results = array();
for ($i = -5.00; $i < 5.00; $i+= 0.1){
	array_push($test_results, HyperbolicTangent($i));
}
var_dump($test_results);

/*
Results of Hyperbolic Tangent (TanH) Function:

-0.99990920426259
-0.99988910295055
-0.99986455170076
-0.9998345655543
-0.99979794161218
-0.99975321084803
-0.99969857928388
-0.99963185619007
-0.99955036645953
-0.9994508436878
-0.99932929973907
-0.99918086567003
-0.99899959778584
-0.99877824128113
-0.99850794233233
-0.9981778976112
-0.99777492793428
-0.99728296009914
-0.99668239783965
-0.9959493592219
-0.99505475368673
-0.99396316735058
-0.99263152020113
-0.99100745367812
-0.9890274022011
-0.98661429815143
-0.98367485769368
-0.98009639626619
-0.97574313003145
-0.97045193661345
-0.96402758007582
-0.95623745812774
-0.94680601284627
-0.9354090706031
-0.92166855440647
-0.90514825364487
-0.88535164820226
-0.86172315931331
-0.83365460701216
-0.80049902176063
-0.76159415595577
-0.71629787019902
-0.66403677026785
-0.60436777711716
-0.53704956699804
-0.46211715726001
-0.37994896225523
-0.29131261245159
-0.19737532022491
-0.099667994624957
-1.0547118733939E-15
0.099667994624955
0.1973753202249
0.29131261245159
0.37994896225522
0.46211715726001
0.53704956699803
0.60436777711716
0.66403677026785
0.71629787019902
0.76159415595576
0.80049902176063
0.83365460701216
0.86172315931331
0.88535164820226
0.90514825364487
0.92166855440647
0.9354090706031
0.94680601284627
0.95623745812774
0.96402758007582
0.97045193661345
0.97574313003145
0.98009639626619
0.98367485769368
0.98661429815143
0.9890274022011
0.99100745367812
0.99263152020113
0.99396316735058
0.99505475368673
0.9959493592219
0.99668239783965
0.99728296009914
0.99777492793428
0.9981778976112
0.99850794233233
0.99877824128113
0.99899959778584
0.99918086567003
0.99932929973907
0.9994508436878
0.99955036645953
0.99963185619007
0.99969857928388
0.99975321084803
0.99979794161218
0.9998345655543
0.99986455170076
0.99988910295055
0.99990920426259

*/



?>