Data commit

Task/Pells-equation/Zkl/pells-equation-1.zkl

@@ -0,0 +1,17 @@
+var [const] BI=Import("zklBigNum");  // libGMP
+
+fcn solve_pell(n){
+   x,y,z,r := BI(n).root(2),  x.copy(),  BI(1),  x*2;
+   e1,e2, f1,f2 := BI(1), BI(0),  BI(0), BI(1);
+   reg t;	// a,b = c,d is a=c; b=d
+   do(30_000){  // throttle this in case of screw up
+      y,z,r = (r*z - y),  (n - y*y)/z,  (x + y)/z;
+
+      t,e2,e1 = e2,  r*e2 + e1,  t;
+      t,f2,f1 = f2,  r*f2 + f1,  t;
+
+      A,B := e2 + x*f2, f2;
+
+      if (A*A - B*B*n == 1) return(A,B);
+   }
+}

Task/Pells-equation/Zkl/pells-equation-2.zkl

@@ -0,0 +1,4 @@
+foreach n in (T(61, 109, 181, 277)){
+   x,y:=solve_pell(n);
+   println("x^2 - %3d*y^2 = 1 for x = %-21d and y = %d".fmt(n,x,y));
+}