program mathpak;
{(C) Australian Computer Society 1984}
{based on paper A Compact Mathematical Function Package
  by A.P. Clarke and W. Marwood,
  The Australian Computer Journal,
  Vol 16, No 3, August 1984, pp 107 to 114
  entered by W F McGee 1 Dec 1984}
const e=1.0e4;
      sqrt_pi=1.772453850905;
      sqrt2  =1.414213562373;
      eul    =0.577215664901;
      sqrt12 =3.464101615137;
      ln2    =0.693147180559;
      ln10   =2.302585092994;
      ln17   =2.833213344056;
      TERMMAX=500;
type available=(sif,cif,e1f,jnf,mbif,lagf,qf,phif,erff,erfcf,
     chgf2f,sxf,cxf,qmnf,pmnf,hf,gmf,hgff,chgf1f,ghgff,cf,sf,
     expf,lf,l10f,done);
     string25=string[25];
var prec:real;
    numparm:array[available]of integer;
    name:array[available]of string25;
    sig_dig:integer;
    sig_dig_flag:boolean;
    sig_dig_real,Ubound,lngmb,gmb,mc_dig:real;
    x:real;
{**********************************************************}
function lnn(x:real):real;
{natural log with zero exception}
begin
  if x=0 then lnn:=-86 else lnn:=ln(x)
{IMPLEMENTATION DEPENDENT  38*ln10}
end;
{***********************************************************}
procedure sum_error(var1,dig1,var2,dig2:real);
var error:real;
begin
  error:=abs(var1)*(exp(-dig1*ln10)+prec) +
         abs(var2)*(exp(-dig2*ln10)+prec);
  sig_dig:=trunc(ln(abs((var1+var2)/error))/ln10)
end;
{**************