AMBER: Strange behavior on g95 compile.

From: Martin Stennett <>
Date: Wed, 07 Feb 2007 16:00:23 +0000

I have a fully working version of amber compiled on another machine in
my department. I copied the source code accross to this machine, where I
have to use a different compiler.
on compiling a serial version of sander I get an error:

g95 -c -O3 -fno-second-underscore -ffree-form -I../../sander -o
../obj/random.o ../obj/random.f
In file ../obj/random.f:11

FUNCTION xrandom(idum)
Warning (139): Value of function 'xrandom' at (1) is never set
In file ../obj/random.f:22

FUNCTION irandom(idum,imax)
Warning (139): Value of function 'irandom' at (1) is never set
In file ../obj/random.f:11

FUNCTION xrandom(idum)
In file ../obj/random.f:47

     sum = sum + xrandom(idum)
Error: FUNCTION 'xrandom' is of type REAL(4) at (1) and type REAL(8) at (2)
make[2]: *** [../obj/random.o] Error 1

I was able to prevent this error message appearing and complete the
compilation of sander by changing line 13 in
$AMBERHOME/src/dcqtp/src/util/random.F90 to read:
 implicit double precision(a-h, o-z)
where before no code was included in the function xrandom(idum).

Once sander has been made in this way when I run it it behaves very very
oddly, for intance when simulating a box of just 375 TIP3P water
molecules at 273 K it's first action is to drop the temperature of the
simulation to ~60K and continue at that temperature.

Can anyone point me towards a fix for this?

 Martin Stennett.
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Received on Sun Feb 11 2007 - 06:07:08 PST
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