search for: z_atan

Hi the following gave me a shock: > atan(2) [1] 1.107149 > atan(2+0i) [1] -0.4636476+0i > or, perhaps more of a gotcha: > atan(1.0001+0i) [1] -0.7853482+0i > atan(0.9999+0i) [1] 0.7853482+0i > evidently atan()'s branch cuts aren't where I thought they were. Where do I look for documentation on this? -- Robin Hankin Uncertainty Analyst National

...`ccos' complex.o(.text+0xc38): In function `z_sin': /usr/local/R-alpha/src/main/complex.c:491: undefined reference to `csin' complex.o(.text+0xc5e): In function `z_tan': /usr/local/R-alpha/src/main/complex.c:497: undefined reference to `ctan' complex.o(.text+0xd26): In function `z_atan2': /usr/local/R-alpha/src/main/complex.c:523: undefined reference to `catan' complex.o(.text+0xe18): In function `z_asin': /usr/local/R-alpha/src/main/complex.c:541: undefined reference to `casin' complex.o(.text+0xe38): In function `z_acos': /usr/local/R-alpha/src/main/complex....