[ccp4bb]: CCP4 on RedHat 7: conclusions and recommended action

[Kevin Cowtan <cowtan@ysbl.york.ac.uk>]

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If you are running CCP4 on an out-of-box RedHat 7 machine, CHECK YOUR
INSTALLATION NOW.
Your results may be unreliable.

Unfortunately there are so many variables that the only way to be sure
seems to be to run the refmac5_tls.exam in $CEXAM/unix/runnable: this
should stop after 20 cycles with an Free R-factor of sbout 0.198. It
would be useful if as many people as possible could tell us whether this
script works, along with their gcc and glibc versions.

Refmac shows these problems most clearly, because it performs the most
complex calculations, but most other programs are likely to be affected
to a greater or lesser extent.

Garib's little test program fails here at > -O1 using the default RedHat
7 compiler (gcc-2.96-54) and an updated glibc (glibc-2.1.94-3). Type
'rpm -q gcc glibc' to check if you are running these version. There seem
to be other problems at -O1 for the later gcc-2.96-69, although it runs
Garib's small test OK. In other words:

2.95-1:   Works for Garib's demo, and for refmac at -O2
2.96-54:  May fail for Garib's demo, fails for CCP4 libraries and
refmac5 -O1
2.96-69:  Works for Garib's demo, may fail for CCP4 libraries or refmac5
-O1

I installed gcc-2.95-1 (an older version), which gives the correct
results from the refmac5_tls.exam example script. Garib reports success
with refmac even at -O2

I have made a tar file of the resulting binary distribution. This comes
with no warrenty of any sort. If your local laws forbid `no warrenty'
clauses, then you are forbidden from downloading this file. Otherwise,
pick it up from:
  ftp://ftp.ysbl.york.ac.uk/pub/ccp4/ccp4-4.1-rh7.tar.gz  (20Mb)
This contains only the bin and lib directories: install it over the top
of your normal installation.


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Alternatively, you can install a new compiler on your system. I outline
how to do this below without losing the current ones, but it is not for
the faint-hearted. The following instructions will probably wreck your
system and destroy your data - don't do it:

First download you desired packages. I used gcc-2.95.1-3 and
gcc-g77-2.95.1-3
on Kay's recommendation, from
ftp://sunsite.auc.dk/disk1/redhat-contrib/libc6/i386/
2.95-2 is also well thought of.

Now you need to unpack the files without overwriting your existing
compilers.
 cp gcc*rpm /tmp
 cd /tmp
 rpm2cpio gcc-2.95.1-3.rpm | cpio -i -d --no-absolute-filenames 
 rpm2cpio gcc-g77-2.95.1-3.rpm | cpio -i -d --no-absolute-filenames 

(This trick can also be useful for installing software without root
access, but it won't work in this case).

Now we su root and copy the compiler files into their version specific
location:
 cp -r /tmp/usr/lib/gcc-lib/i386-redhat-linux/2.95.1
/usr/lib/gcc-lib/i386-redhat-linux/

Finally copy the binaries:
 cp /tmp/usr/bin/gcc /usr/bin/gcc_2.95-1
 cp /tmp/usr/bin/g77 /usr/bin/g77_2.95-1

Now exit root and set your environment variables to pick up the new
compilers
 setenv CC gcc_2.95-1
 setenv FC g77_2.95-1

Now go back and re-run the ccp4 configure script, then make. You should
see the new compiler being used for everything expect maybe ccif.