How do I calculate the complex argument in Fortran?

[miccol999]

Hi
I need help with programming the following:

(T/(T-2*d))^(i*Nu)=exp(-i*Nu*ln|T/(T-2*d)| +Nu*arg(T/(T-2*d))

I don't know how to do the arg bit in Fortran90...this is what I've tried so far

A=T/(T-2*DELTA)
B=EXP(-CI*NU*LOG(ABS(A))+NU*ARG(A))

but obviously it threw back an error message at the 'ARG(A)' bit...I've tried searching the web and help directories but still unsure as to what to do, HELP!

 

[miccol999]

I've also tried the following...

A=T/(T-2*DELTA)
ARGA=ATAN(REAL(AIMAG(A))/REAL(REAL(A)))
B=EXP(-CI*NU*LOG(ABS(A))+NU*ARGA)

...since arg(x+iy)=tan^(-1)(y/x). I think I'm not using the right function to find the real and imaginary parts of A, can anyone help at all?

 

[Dr Transport]

atan2(real(A),imag(A)), if that isn't right, reverse the arguments.

 

[miccol999]

that didn't work...how do you get arg(z) in fortran?

 

[hutxubix]

Ten en cuenta que usas ATAN2 si es simple presicion y DATAN2 si es doble presicion

ATAN2(parte imaginaria, parte real)

Parte imaginaria: IMAG (o AIMAG) y DIMAG (Simple y doble presicion)
Parte real: REAL o DREAL

Examples

ATAN2 (2.679676, 1.0) has the value 1.213623.