Initial data commit

Task/Gamma-function/ANSI-BASIC/gamma-function.basic

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+100 DECLARE EXTERNAL FUNCTION FNlngamma
+110
+120 DEF FNgamma(z) = EXP(FNlngamma(z))
+130
+140 FOR x = 0.1 TO 2.05 STEP 0.1
+150    PRINT USING$("#.#",x), USING$("##.############", FNgamma(x))
+160 NEXT x
+170 END
+180
+190 EXTERNAL FUNCTION FNlngamma(z)
+200 DIM lz(0 TO 6)
+210 RESTORE
+220 MAT READ lz
+230 DATA 1.000000000190015, 76.18009172947146, -86.50532032941677, 24.01409824083091, -1.231739572450155, 0.0012086509738662, -0.000005395239385
+240 IF z < 0.5 THEN
+250    LET FNlngamma = LOG(PI / SIN(PI * z)) - FNlngamma(1.0 - z)
+260    EXIT FUNCTION
+270 END IF
+280 LET z = z - 1.0
+290 LET b = z + 5.5
+300 LET a = lz(0)
+310 FOR i = 1 TO 6
+320    LET a  = a + lz(i) / (z + i)
+330 NEXT i
+340 LET FNlngamma = (LOG(SQR(2*PI)) + LOG(a) - b) + LOG(b) * (z+0.5)
+350 END FUNCTION