71 & 75 Math ROMs, Series 80 Matrix ROM

[J-F Garnier]

Thanks, Valentin, for your valuable comments.

Quote:2) The HP-71B Math ROM can't compute the determinant of a complex matrix.

Thanks for pointing this mistake in my document. The 71 Math ROM manual indeed specifies that DET is applicable to a real matrix only.

Quote:3) The ease of use of complex functionalities in the HP-71B is an order of magnitude over the ones in the HP-75C, which are clumsy, time-wasting and RAM-wasting in the extreme.

Sure. However, the complex functions of the 75 Math ROM has been implemented years after the initial 75 design and introduction. The 71 has (apparently) been designed with the complex support in mind right from the beginning.

Quote: ... Besides, the functions left out in the 75C's, namely SIGN and ABS aren't as trivial as those for the real case.

ABS and ARG can be easily obtained from the rectangular to polar conversion. Then SIGN can be calculated using the ABS value. Of course, this requires several operations, but is much less difficult than implementing the missing 71's inverse trigonometric and hyperbolic functions in the complex domain :-)
I didn't want to include workarounds for the missing functions, it was not my goal (that was to compare the features). The 75 Math ROM manual provides procedures to implement additional features, such as multiplying a complex matrix by a real scalar, or creating the complex form of a real matrix, things that the 71 Math ROM can do in one operation but not the 75.

Quote:4) The implementation of FNROOT and INTEGRAL in the HP-71B Math ROM is not just "better" than the one for the HP-75C, it's dramatically better, ...

I tend to agree with you. The implementation is better regarding the more flexible way to define the function, and is more powerful because it can solve more complicate problems thanks to the nested calls.

J-F