Bob, your program can probably calculate the input impedance, Rin + j*Xin,
of a line having Zo = Ro + j*Xo, with given attenuation Alpha dB, and given
phase-shift Beta radians, with a terminating impedance Rt + j*Xt.

Which is a commonly needed quantity on the way to calculating the ultimate,
all-important, single number, transmission efficiency.

But can you do it with nothing at hand except a Smith Chart?
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Yours, Reg.