Brian Dunning's FileMaker Custom Functions

ErrorFunctionInverse ( x )

Calculates the inverse error function via Taylor series expansion

  Average rating: 4.4 (28 votes) Log in to vote

Jeremy Bante   Jeremy Bante

http://github.com/jbante

Share on Facebook Share on Twitter

  Sample input:
List (
ErrorFunctionInverse ( -.8 ) ;
ErrorFunctionInverse ( -.6 ) ;
ErrorFunctionInverse ( -.4 ) ;
ErrorFunctionInverse ( -.2 ) ;
ErrorFunctionInverse ( 0 ) ;
ErrorFunctionInverse ( .1 ) ;
ErrorFunctionInverse ( .3 ) ;
ErrorFunctionInverse ( .5 ) ;
ErrorFunctionInverse ( .7 ) ;
ErrorFunctionInverse ( .9 )
)
  Sample output:
-.90619380243681129116239661400140183641072811603236
-.59511608144999483099716019972985021912702246342263
-.37080715859355792771730281906148776800110420959213
-.17914345462129167542107793245150434382489250138362
0
.0888559904942577
.27246271472675435351518042903635524518984326931916
.47693627620446987015027371023187301092338722790087
.73286907795921666827066321704975849515295969428148
1.16308715364904662588930164987257155615356517332946

  Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

Returns the inverse error function of x (commonly represented as erfinv(x) in other programming environments). The calculation happens by means of a Taylor/Maclaurin series expansion. The coefficients for the terms of the series are memoized in variables to improve performance in repeated calls to the function within the same local scope.

 

Comments

Log in to post comments.

 

Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.

Support this website.

This library has been a free commmunity resource for FileMaker users and developers for 15 years. It receives no funding and has no advertisements. If it has helped you out, I'd really appreciate it if you could contribute whatever you think it's worth:

Under construction. Email me your wish list for improvements.