Turn Ackermann function into a virtual stack [even more memory-compact version without currentStep field] [1030379]

< > BotCompany Repo | #1030379 // Turn Ackermann function into a virtual stack [even more memory-compact version without currentStep field]

JavaX source code (Dynamic Module) [tags: use-pretranspiled] - run with: Stefan's OS

cprint {
  srecord f_ackermann(BigInt a, BigInt b) implements VStack.Computable<BigInt> {
    void step(VStack stack, O subComputationResult) {
      if (!stack.hasSubResult()) {
        if (a.equals(BigInt.ZERO))
          stack._return(plus(b, BigInt.ONE));
        else if (b.equals(BigInt.ZERO))
          stack.tailCall(new f_ackermann(a.subtract(BigInt.ONE), BigInt.ONE);
        else
          stack.push(new f_ackermann(a, minus(b, BigInt.ONE)));
      } else
        stack.tailCall(new f_ackermann(minus(a, BigInt.ONE), subComputationResult/BigInt));
    }
  }
  
  start-thread {
    print("Result: " + vStackComputeWithStats(new f_ackermann(bigInt(2), bigInt(2))));
    
    // detailed run
    VStack stack = new(new f_ackermann(bigInt(2), bigInt(2)));
    printStruct(stack);
    while ping (stack.step()) {
      printStruct(stack);
      stack = restructure(stack); // persist to string and re-create
    }
  }
}

Author comment

Began life as a copy of #1030378

Travelled to 4 computer(s): bhatertpkbcr, mqqgnosmbjvj, pyentgdyhuwx, vouqrxazstgt

Snippet ID:

#1030379

Snippet name:

Turn Ackermann function into a virtual stack [even more memory-compact version without currentStep field]

Eternal ID of this version:

#1030379/9

Text MD5:

c60903f5e18e3a00b7912c6eba1efe59

Transpilation MD5:

f3e461c937b69145c31e2e75c866fba7

Author:

stefan

Category:

javax / maths

Type:

JavaX source code (Dynamic Module)

Public (visible to everyone):

Yes

Archived (hidden from active list):

Created/modified:

2021-04-18 14:53:03

Source code size:

953 bytes / 27 lines

Pitched / IR pitched:

No / No

Views / Downloads:

207 / 325

Version history:

8 change(s)

Referenced in:

[show references]

1	cprint {
2	srecord f_ackermann(BigInt a, BigInt b) implements VStack.Computable<BigInt> {
3	void step(VStack stack, O subComputationResult) {
4	if (!stack.hasSubResult()) {
5	if (a.equals(BigInt.ZERO))
6	stack._return(plus(b, BigInt.ONE));
7	else if (b.equals(BigInt.ZERO))
8	stack.tailCall(new f_ackermann(a.subtract(BigInt.ONE), BigInt.ONE);
9	else
10	stack.push(new f_ackermann(a, minus(b, BigInt.ONE)));
11	} else
12	stack.tailCall(new f_ackermann(minus(a, BigInt.ONE), subComputationResult/BigInt));
13	}
14	}
15
16	start-thread {
17	print("Result: " + vStackComputeWithStats(new f_ackermann(bigInt(2), bigInt(2))));
18
19	// detailed run
20	VStack stack = new(new f_ackermann(bigInt(2), bigInt(2)));
21	printStruct(stack);
22	while ping (stack.step()) {
23	printStruct(stack);
24	stack = restructure(stack); // persist to string and re-create
25	}
26	}
27	}