[RFC]: add C implementation for `@stdlib/math/base/special/erfcx`

[USERSATOSHI]

Description

This RFC proposes a C implementation for @stdlib/math/base/special/erfcx

double stdlib_base_erfcx( const double x ) 

Related Issues

Related issues #649

Questions

No.

Other

@stdlib/math/base/special/erfcx is dependent on following packages:

• PINF : already implemented in C
• exp : already implemented in C
• floor : already implemented in C

Checklist

• I have read and understood the Code of Conduct.
• Searched for existing issues and pull requests.
• The issue name begins with RFC:.

[USERSATOSHI]

A question regarding erfcx_y100.js, as the erfcx_y100.js implements 100 functions and put them in a lookup table should we try for same approach in C or go for a much simpler switch statement

[noobCoderVP]

Hey there, I would like to work on this issue, can you please assign this issue to me?

[kgryte]

@USERSATOSHI I think we should be consistent with the JS implementation. From a logic POV, not any more "complex" than a switch statement.

[USERSATOSHI]

@USERSATOSHI I think we should be consistent with the JS implementation. From a logic POV, not any more "complex" than a switch statement.

thank you for responding , I will then implement with lookup table

[USERSATOSHI]

I had one more question

static double erfcxY100( const double y100 ) {
    double t;
    double(*f)(const double);

    t = stdlib_base_floor( y100 );
    f = table[ (int)t ];
    return f( 2*y100 - ((2*t) + 1)  );
}

are we allowed to type cast as table needs t as int while floor returns a double accordingly

[kgryte]

Yes, that should be fine.

[USERSATOSHI]

Yes, that should be fine.

thank you for informing