EXPORT PI_CALC_B()
BEGIN
  LOCAL digits=1000 ;  // 計算する桁数
  LOCAL k := 8 ;         // 変数あたりの桁数

  INPUT(digits,"計算桁数","digits=","計算する桁数",1000,100);
  INPUT(k,"変数あたりの桁数","base=","変数の桁数",8,8);

  LOCAL base := 10^k ;   // 基底
  LOCAL ARRYS := floor((digits+k-1)/k)+1; // 配列数
  LOCAL f := floor(digits/log(2))+1  ; // 計算項数
  LOCAL i, n, g, w, cy, s, t;
  LOCAL skip:=0;
  LOCAL str0, str1;

  //  配列　初期化
  L4:=MAKELIST(0.0,X,1,ARRYS,1);

  print();
  print("計算桁数="+digits+"桁   ("+(k)+"桁*"+(ARRYS)+")");
  print("計算項数 "+f);

  s:=TICKS;

  FOR n FROM f DOWNTO 1 DO

    cy := 0;
    FOR i FROM ARRYS DOWNTO 1 DO
    //  A * n -> A
      w := L4(i)*n+cy;
      cy := floor(w/base);
      L4(i) := w-cy*base;
    END;

    //  A / (n*2+1) -> A
    g := n*2+1;
    FOR i FROM 1 TO ARRYS DO
      t := cy*base+L4(i);
      w := floor(t / g);
      cy := t - w*g;
      L4(i) := w;
    END;

    //  A + 2 -> A
    L4(1) := L4(1)+2;

    IF (TICKS>skip+100) THEN
      skip:=TICKS;
      TEXTOUT_P("残りループ数="+n+"   ", 0, 70,0,#0,160,#FFFFFF);
      t:=TICKS-s;
      TEXTOUT_P("経過時間: "+t/1000+"秒",0,100,0,#0,160,#FFFFFF);
    END;

  END;

  t:=TICKS;
  print("計算時間: "+(t-s)/1000+"秒");
  print("PI=3.");
  str1 := "";                          // 10桁整形
  FOR i FROM 2 TO ARRYS DO
     str0 := string(L4(i));
     WHILE dim(str0)<k DO
        str0 := "0"+str0;
     END;
     str1 := str1+str0;
  END;
  str0 := "";
  i := 0;
  WHILE i<digits DO
     IF digits-i>=10 THEN
       str0 := str0+left(str1,10) + " ";
       str1 := mid(str1,11);
     ELSE
       str0 := str0+left(str1,digits-i);
     END;
     i := i+10;
  END;
  print(str0);

END;