(42S) Argument, Real Part, Imaginary Part, and Sign Function

12292018, 05:25 AM
Post: #1




(42S) Argument, Real Part, Imaginary Part, and Sign Function
The HP 42S* has only one extraction function for complex numbers: ABS (absolute value) by default. To complete the list, here are some programs for ARG (argument), REAL (real part), and IMAG (imaginary part). The three functions take a complex number, in either rectangular or polar form.
Using stack commands and flag checks, I am able to get obtain results without affecting the stack much (although the z and t stacks will have the same value). Also included is the SIGN (signum) function. * This applies to the Swiss Micros DM42 (it should work), Free42 from Thomas Oakken, and any other HP 42S emulator apps. The print out is from Free42 (and I also have a physical HP 42S). Disclaimer: I don't own a DM42... yet. HP 42S Program: ARG Code:
HP 42S Program: REAL Code:
HP 42S Program: IMAG Code:
HP 42S Program: SIGN Code:
Original Blog Entry Link: https://edspi31415.blogspot.com/2018/12/...part.html 

12292018, 05:48 AM
Post: #2




RE: (42S) Argument, Real Part, Imaginary Part, and Sign Function
What about:
Code: LBL "SIGN" Which (I think, I've no 42 to hand) sets LastX properly and doesn't impact the stack. Pauli 

12292018, 06:35 AM
Post: #3




RE: (42S) Argument, Real Part, Imaginary Part, and Sign Function  
12292018, 08:50 AM
Post: #4




RE: (42S) Argument, Real Part, Imaginary Part, and Sign Function
(12292018 05:48 AM)Paul Dale Wrote: What about: This would work if (!) the 42s allowed tests for complex numbers. ;) But it throws an "Invalid Type" error here. (12292018 06:35 AM)Thomas Klemm Wrote: What about using the builtin SIGN function? Yes, a complex sign function is not required, the builtin function works nicely. For complex arguments it even returns 0 for 0+0i. For real arguments sign(0) is returned as 1. Maybe for compatibility with the HP41 which does it the same way. Here SIGN returns 0 only for Alpha data (!). Dieter 

12302018, 07:12 PM
Post: #5




RE: (42S) Argument, Real Part, Imaginary Part, and Sign Function
On my real HP 42S
SIGN returns 0+0i for input 0+0i 

12302018, 08:19 PM
(This post was last modified: 12302018 08:20 PM by Dieter.)
Post: #6




RE: (42S) Argument, Real Part, Imaginary Part, and Sign Function  
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