norm2 for complex vectors

[diedro]

dear all,

I usually use NORM2 to compute the error in a while cycle.

However, I have complex vector now and NORM2 does not work.

Is there any norm2 function for complex vectors?

Thanks 

[Steven_L_Intel1]

Not in the Fortran standard - NORM2 is defined for REAL only.

[diedro]

Dear all, Dear Steve,

Ok. Do you have some suggestion to overcome this?

this is my code, I use norm2 to compute the error:

 DO WHILE(NORM(R1)>=eps*NORM(BBg))
        !
        P1 = R1 + beta0*P0
       !
       ........
       ........
      .........
   ENDDO
    

where R1 and BBg are complex vectors

Thanks for any help

[TimP]

You'd have to specify explicitly how you want NORM calculated.
 

[mecej4 · Accepted solution]

There is a routine NRM2 in MKL, of which the flavors SCNRM2 and DZNRM2  pertain to complex vectors. There is an overloaded routine NRM2 available through the F95 interface.

[JVanB]

I can't understand at all why NORM2 for complex input isn't in the standard. Stuff like NORM2(transfer(x,[real(kind(x))::])) or NORM2([NORM2(real(x)),NORM2(aimag(x))]) is possible.

[diedro]

Dear all,

thanks a lot. 

NRM2 and NORM2([NORM2(real(x)),NORM2(aimag(x))]) work for me.

I have only to compute the difference between two complex vectors

thanks again