read and use environment variable PARI_SIZE

README

@@ -30,7 +30,8 @@ run: either (i) after ./configure, edit ./Makefile and all */Makefile,
 setting FLINT_LEVEL=2 (instead of =1); or (ii) edit configure itself
 similarly (in two places) and rerun it; or (iii) append
 CXXFLAGS='-DFLINT_LEVEL=2' to the make invocation (and ignore warnings
-about FLINT_LEVEL being redefined).
+about FLINT_LEVEL being redefined).   To carry out (ii): run
+sed -i '/FLINT_LEVEL/s/1/2/' configure
 
 (c) Boost is optional (from eclib-2013-09-00) and provides parallel
 capabilities in the form_finder class. Configure with --with-boost

configure.ac

@@ -3,7 +3,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.65])
-AC_INIT([eclib], [20170711], [john.cremona@gmail.com])
+AC_INIT([eclib], [20170815], [john.cremona@gmail.com])
 AM_INIT_AUTOMAKE([-Wall])
 AC_MSG_NOTICE([Configuring eclib...])
 AC_CONFIG_SRCDIR([libsrc])
@@ -36,7 +36,7 @@ LT_INIT
 # NB The suffix of the library name (libec.so here) is (c-a).a.r
 
 LT_CURRENT=3
-LT_REVISION=7
+LT_REVISION=8
 LT_AGE=0
 AC_SUBST(LT_CURRENT)
 AC_SUBST(LT_REVISION)

doc/mwrank/mwrank.info

@@ -237,7 +237,13 @@ You can aid the factorization of large integers in several ways:
 
 (a) Pari (i.e. the library libpari) is now a requirement, and is used
 to factorization of integers greater than a bound set to 10^8 in
-libsrc/marith.cc.  This is the only use made of the Pari library.
+libsrc/marith.cc.  This is the only use made of the Pari library.  By
+default the pari library is initialized with parisize=1000000.  If you
+see an error message saying " [hint] set 'parisizemax' to a non-zero
+value in your GPRC" do not follow the hint (which is wrong, we are not
+using gp at all) but instead set the environment variable PARI_SIZE to
+some larger value (e.g. do "export PARI_SIZE=100000000" but this will
+depend on your system).
 
 (b) By default the programs initialise an array of primes < 10^6, so
 will succeed in factoring all numbers < 10^8 by trial division.  This
@@ -272,4 +278,4 @@ John Cremona (john.cremona@gmail.com)
 
  3 February 1995, updated 12 January 1998, 25 September 2000, 5 July 2001,
  12 November 2003, 5 January 2005, 10 May 2005, 31 December 2011, 2
- January 2016.
+ January 2016, 15 August 2017.

libsrc/eclib/interface.h

@@ -301,4 +301,9 @@ inline int is_approx_zero(const bigcomplex& z)
 
 #undef setbit
 
+// Utility to return a string from an environment variable with a
+// default to use if the variable is not set or empty.
+
+string getenv_with_default(string env_var, string def_val);
+
 #endif // #define _INTERFACE_H_

libsrc/eclib/moddata.h

@@ -63,11 +63,6 @@ class moddata :public level {
  long unitdiv(long res) const {return unitdivlist[reduce(res)];}
 };
 
-// Utility to return a string from an environment variable with a
-// default to use if the variable is not set or empty.
-
-string getenv_with_default(string env_var, string def_val);
-
 // Returns oldform filename. Default is "newforms/", but can
 // be changed via OF_DIR environment variable.
 string of_filename(long n, char c);

libsrc/interface.cc

@@ -307,5 +307,16 @@ istream& operator>>(istream& is, CC& z)
   return is;
 }
 
+string getenv_with_default(string env_var, string def_val)
+{
+  stringstream s;
+  if (getenv(env_var.c_str()) != NULL) {
+    s << getenv(env_var.c_str());
+  } else {
+    s<<def_val;
+  }
+  return s.str();
+}
+
 #endif // NTL_ALL
 

libsrc/moddata.cc

@@ -147,17 +147,6 @@ void moddata::display() const
  cout << "unitdivlist: " << unitdivlist << endl;
 }
 
-string getenv_with_default(string env_var, string def_val)
-{
-  stringstream s;
-  if (getenv(env_var.c_str()) != NULL) {
-    s << getenv(env_var.c_str());
-  } else {
-    s<<def_val;
-  }
-  return s.str();
-}
-
 string of_filename(long n, char c)
 {
   stringstream s;

libsrc/parifact.cc

@@ -21,9 +21,11 @@
 // 
 //////////////////////////////////////////////////////////////////////////
 
+#include <eclib/interface.h> // for getenv_with_default
 #include <pari/pari.h>
 #include <eclib/parifact.h>
 
+
 //#define DEBUG_GPFACT
 
 #include <iostream>
@@ -33,7 +35,13 @@ string
 factor(const string n)
 {
   if (!avma) {
-    pari_init(1000000, 1000000);
+    long pari_size = strtol(getenv_with_default("PARI_SIZE", "100000").c_str(), NULL, 0);
+    if (pari_size==0) // e.g. syntax error in the environment variable PARI_SIZE
+      pari_size = 1000000;
+#ifdef DEBUG_GPFACT
+    std::cout<<"calling pari_init with pari_size = "<<pari_size<<endl;
+#endif
+    pari_init(pari_size, 1000000);
   }
 #ifdef DEBUG_GPFACT
   std::cout<<"factor called with "<<n<<endl;
@@ -46,6 +54,9 @@ factor(const string n)
   settyp(x,t_VEC);
 
   string ans(GENtostr(x));
+#ifdef DEBUG_GPFACT
+  std::cout<<"factor returns "<<ans<<endl;
+#endif
   avma=av;         // restore pari stackpointer
   return ans;
 }
@@ -54,7 +65,13 @@ int
 is_prime(const string p)
 {
   if (!avma) {
-    pari_init(1000000, 1000000);
+    long pari_size = strtol(getenv_with_default("PARI_SIZE", "100000").c_str(), NULL, 0);
+#ifdef DEBUG_GPFACT
+    std::cout<<"calling pari_init with pari_size = "<<pari_size<<endl;
+#endif
+    if (pari_size==0) // e.g. syntax error in the environment variable PARI_SIZE
+      pari_size = 1000000;
+    pari_init(pari_size, 1000000);
   }
   pari_sp av=avma;  // store pari stack pointer