Hewlett-Packard HP-17B
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Ab/c:
Fractions calculation
AC: Alternating current BaseN: Number base calculations Card: Magnetic card storage Cmem: Continuous memory Cond: Conditional execution Const: Scientific constants Cplx: Complex number arithmetic DC: Direct current Eqlib: Equation library Exp: Exponential/logarithmic functions Fin: Financial functions Grph: Graphing capability Hyp: Hyperbolic functions Ind: Indirect addressing Intg: Numerical integration Jump: Unconditional jump (GOTO) Lbl: Program labels LCD: Liquid Crystal Display LED: Light-Emitting Diode Li-ion: Lithium-ion rechargeable battery Lreg: Linear regression (2-variable statistics) mA: Milliamperes of current Mtrx: Matrix support NiCd: Nickel-Cadmium rechargeable battery NiMH: Nickel-metal-hydrite rechargeable battery Prnt: Printer RTC: Real-time clock Sdev: Standard deviation (1-variable statistics) Solv: Equation solver Subr: Subroutine call capability Symb: Symbolic computing Tape: Magnetic tape storage Trig: Trigonometric functions Units: Unit conversions VAC: Volts AC VDC: Volts DC |
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Hewlett-Packard HP-17B
The HP-17B is a high-end business calculator from Hewlett-Packard. This is not a keystroke-programmable machine; instead, it has a built-in "SOLVE" feature that lets you enter mathematical formulae, which the calculator can solve for unknown variables.
The particular version of the "SOLVE" feature implemented on this machine has two special features: conditional execution and loops. The IF function can evaluate one of two expressions depending on whether a specific condition is true or false; the Σ function can be used to evaluate an expression repetitively, calculating the sum.
With these two functions and the calculator's relatively large memory, it is possible to implement fairly sophisticated solutions. One example is the Gamma function; the implementation I present here actually includes an iterative component that extends the function's domain to negative numbers. Despite the length and complexity, the calculator evaluates the function very quickly; what takes time is the verification of the equation when the "SOLVE" feature is invoked.
G=(-1)^Σ(I:X:0:1:1)×EXP(LN(2.50662827511×(X+Σ(I:X:0:1:1))^6+ 83.8676043424×(X+Σ(I:X:0:1:1))^5+1168.92649479×(X+Σ(I:X:0:1:1))^4+ 8687.24529705×(X+Σ(I:X:0:1:1))^3+36308.2951477×(X+Σ(I:X:0:1:1))^2+ 80916.6278952×(X+Σ(I:X:0:1:1))+75122.633153)- Σ(I:0:6:1:LN(X+Σ(J:X:0:1:1)+I))+(X+Σ(I:X:0:1:1)+.5)× LN(X+Σ(I:X:0:1:1)+5.5)-X-Σ(I:X:0:1:1)-5.5-Σ(I:X:0:1:LN(-I)))
